有没有一种简单的方法来检查 .NET Framework 版本？

Question

问题是我需要知道它是否是版本 3.5 SP 1。Environment.Version() 仅返回 2.0.50727.3053。

我找到了这个解决方案，但我认为这需要时间比其价值多得多，所以我正在寻找一种更简单的方法。 是否可以？

Answer 1

试试这个：

string GetFrameWorkVersion()
    {
        return System.Runtime.InteropServices.RuntimeEnvironment.GetSystemVersion();
    }

Answer 2

像这样的事情应该可以做到。 只需从注册表中获取值

对于 .NET 1-4：

Framework 是安装的最高版本，SP 是该版本的服务包。

RegistryKey installed_versions = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP");
string[] version_names = installed_versions.GetSubKeyNames();
//version names start with 'v', eg, 'v3.5' which needs to be trimmed off before conversion
double Framework = Convert.ToDouble(version_names[version_names.Length - 1].Remove(0, 1), CultureInfo.InvariantCulture);
int SP = Convert.ToInt32(installed_versions.OpenSubKey(version_names[version_names.Length - 1]).GetValue("SP", 0));

对于 .NET 4.5+（来自官方文档） :

using System;
using Microsoft.Win32;


...


private static void Get45or451FromRegistry()
{
    using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\")) {
        int releaseKey = Convert.ToInt32(ndpKey.GetValue("Release"));
        if (true) {
            Console.WriteLine("Version: " + CheckFor45DotVersion(releaseKey));
        }
    }
}


...


// Checking the version using >= will enable forward compatibility,  
// however you should always compile your code on newer versions of 
// the framework to ensure your app works the same. 
private static string CheckFor45DotVersion(int releaseKey)
{
    if (releaseKey >= 528040) {
        return "4.8 or later";
    }
    if (releaseKey >= 461808) {
        return "4.7.2 or later";
    }
    if (releaseKey >= 461308) {
        return "4.7.1 or later";
    }
    if (releaseKey >= 460798) {
        return "4.7 or later";
    }
    if (releaseKey >= 394802) {
        return "4.6.2 or later";
    }
    if (releaseKey >= 394254) {
        return "4.6.1 or later";
    }
    if (releaseKey >= 393295) {
        return "4.6 or later";
    }
    if (releaseKey >= 393273) {
        return "4.6 RC or later";
    }
    if ((releaseKey >= 379893)) {
        return "4.5.2 or later";
    }
    if ((releaseKey >= 378675)) {
        return "4.5.1 or later";
    }
    if ((releaseKey >= 378389)) {
        return "4.5 or later";
    }
    // This line should never execute. A non-null release key should mean 
    // that 4.5 or later is installed. 
    return "No 4.5 or later version detected";
}

Answer 3

不知道为什么没有人建议遵循微软的官方建议此处。

这是他们推荐的代码。 当然它很丑陋，但它有效。

对于 .NET 1-4

private static void GetVersionFromRegistry()
{
     // Opens the registry key for the .NET Framework entry. 
        using (RegistryKey ndpKey = 
            RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, "").
            OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
        {
            // As an alternative, if you know the computers you will query are running .NET Framework 4.5  
            // or later, you can use: 
            // using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine,  
            // RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
        foreach (string versionKeyName in ndpKey.GetSubKeyNames())
        {
            if (versionKeyName.StartsWith("v"))
            {

                RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                string name = (string)versionKey.GetValue("Version", "");
                string sp = versionKey.GetValue("SP", "").ToString();
                string install = versionKey.GetValue("Install", "").ToString();
                if (install == "") //no install info, must be later.
                    Console.WriteLine(versionKeyName + "  " + name);
                else
                {
                    if (sp != "" && install == "1")
                    {
                        Console.WriteLine(versionKeyName + "  " + name + "  SP" + sp);
                    }

                }
                if (name != "")
                {
                    continue;
                }
                foreach (string subKeyName in versionKey.GetSubKeyNames())
                {
                    RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                    name = (string)subKey.GetValue("Version", "");
                    if (name != "")
                        sp = subKey.GetValue("SP", "").ToString();
                    install = subKey.GetValue("Install", "").ToString();
                    if (install == "") //no install info, must be later.
                        Console.WriteLine(versionKeyName + "  " + name);
                    else
                    {
                        if (sp != "" && install == "1")
                        {
                            Console.WriteLine("  " + subKeyName + "  " + name + "  SP" + sp);
                        }
                        else if (install == "1")
                        {
                            Console.WriteLine("  " + subKeyName + "  " + name);
                        }

                    }

                }

            }
        }
    }

}

对于 .NET 4.5 及更高版本

// Checking the version using >= will enable forward compatibility, 
// however you should always compile your code on newer versions of
// the framework to ensure your app works the same.
private static string CheckFor45DotVersion(int releaseKey)
{
   if (releaseKey >= 393295) {
      return "4.6 or later";
   }
   if ((releaseKey >= 379893)) {
        return "4.5.2 or later";
    }
    if ((releaseKey >= 378675)) {
        return "4.5.1 or later";
    }
    if ((releaseKey >= 378389)) {
        return "4.5 or later";
    }
    // This line should never execute. A non-null release key should mean
    // that 4.5 or later is installed.
    return "No 4.5 or later version detected";
}

private static void Get45or451FromRegistry()
{
    using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\")) {
        if (ndpKey != null && ndpKey.GetValue("Release") != null) {
            Console.WriteLine("Version: " + CheckFor45DotVersion((int) ndpKey.GetValue("Release")));
        }
      else {
         Console.WriteLine("Version 4.5 or later is not detected.");
      } 
    }
}

Answer 4

另一种不需要访问注册表的权限的方法是检查特定框架更新中引入的类是否存在。

private static bool Is46Installed()
{
    // API changes in 4.6: https://github.com/Microsoft/dotnet/blob/master/releases/net46/dotnet46-api-changes.md
    return Type.GetType("System.AppContext, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089", false) != null;
}

private static bool Is461Installed()
{
    // API changes in 4.6.1: https://github.com/Microsoft/dotnet/blob/master/releases/net461/dotnet461-api-changes.md
    return Type.GetType("System.Data.SqlClient.SqlColumnEncryptionCngProvider, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089", false) != null;
}

private static bool Is462Installed()
{
    // API changes in 4.6.2: https://github.com/Microsoft/dotnet/blob/master/releases/net462/dotnet462-api-changes.md
    return Type.GetType("System.Security.Cryptography.AesCng, System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089", false) != null;
}

private static bool Is47Installed()
{
    // API changes in 4.7: https://github.com/Microsoft/dotnet/blob/master/releases/net47/dotnet47-api-changes.md
    return Type.GetType("System.Web.Caching.CacheInsertOptions, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", false) != null;
}

Answer 5

我遇到过这样的情况：我的 .NET 4.0 类库可能会从 .NET 4.0 或更高版本的程序集调用。

特定方法调用仅在从 4.5+ 程序集执行时才有效。

为了决定是否应该调用该方法，我需要确定当前执行的框架版本，这是一个非常好的解决方案，可以

var frameworkName = new System.Runtime.Versioning.FrameworkName(
    AppDomain.CurrentDomain.SetupInformation.TargetFrameworkName
);

if (frameworkName.Version >= new Version(4, 5)) 
{
    // run code
}

更新

从 4.0 程序集

它var featureEnabled = GetCurrentFrameworkName().Version >= new Version (4, 5);

public static FrameworkName GetCurrentFrameworkName()
{
    // AppDomain.CurrentDomain.SetupInformation.TargetFrameworkName
    // is missing prior to .NET 4.5
    var targetFrameworkName = (string)AppDomain
        .CurrentDomain
        .SetupInformation
        .GetType()
        .GetProperty("TargetFrameworkName")?
        .GetValue(AppDomain.CurrentDomain.SetupInformation, null) ?? ".NETFramework,Version=v4.0.0";

    return new FrameworkName(targetFrameworkName);
}

Answer 6

Environment.Version() 为另一个问题给出了正确答案。 .NET 2.0、3 和 3.5 中使用相同版本的 CLR。 我想您可以在 GAC 中检查每个后续版本中添加的库。

Answer 7

这曾经很简单，但 Microsoft 决定做出重大更改：在版本 4.5 之前，每个版本的 .NET 都驻留在 C:\Windows\Microsoft.NET\Framework 下的自己的目录中（子目录v1.0.3705、v1.1.4322、v2.0.50727、v3.0、v3.5和v4.0.30319）。

自版本 4.5 起，这一点已更改：.NET 的每个版本（即 4.5.x、4.6.x、4.7.x、4.8.x...）都安装在相同的子目录 v4.0.30319 - 因此您无法再通过查看 Microsoft.NET\Framework 来检查已安装的 .NET 版本。

要检查 .NET 版本，Microsoft 提供了两个不同的示例脚本，具体取决于正在检查的 .NET 版本，但我不喜欢为此使用两个不同的 C# 脚本。
所以我尝试将它们合并为一个，这是我创建的脚本 GetDotNetVersion.cs （并针对 4.7.1 框架更新了它）：

using System;
using Microsoft.Win32;
public class GetDotNetVersion
{
    public static void Main(string[] args)
    {
        Console.WriteLine((args != null && args.Length > 0) 
                          ? "Command line arguments: " + string.Join(",", args) 
                          : "");

        string maxDotNetVersion = GetVersionFromRegistry();
        if (String.Compare(maxDotNetVersion, "4.5") >= 0)
        {
            string v45Plus = GetDotNetVersion.Get45PlusFromRegistry();
            if (v45Plus != "") maxDotNetVersion = v45Plus;
        }
        Console.WriteLine("*** Maximum .NET version number found is: " + maxDotNetVersion + "***");
    }

    private static string Get45PlusFromRegistry()
    {
        String dotNetVersion = "";
        const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";
        using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey))
        {
            if (ndpKey != null && ndpKey.GetValue("Release") != null)
            {
                dotNetVersion = CheckFor45PlusVersion((int)ndpKey.GetValue("Release"));
                Console.WriteLine(".NET Framework Version: " + dotNetVersion);
            }
            else
            {
                Console.WriteLine(".NET Framework Version 4.5 or later is not detected.");
            }
        }
        return dotNetVersion;
    }

    // Checking the version using >= will enable forward compatibility.
    private static string CheckFor45PlusVersion(int releaseKey)
    {
        if (releaseKey >= 528040) return "4.8 or later";
        if (releaseKey >= 461808) return "4.7.2";
        if (releaseKey >= 461308) return "4.7.1";
        if (releaseKey >= 460798) return "4.7";
        if (releaseKey >= 394802) return "4.6.2";
        if (releaseKey >= 394254) return "4.6.1";
        if (releaseKey >= 393295) return "4.6";
        if ((releaseKey >= 379893)) return "4.5.2";
        if ((releaseKey >= 378675)) return "4.5.1";
        if ((releaseKey >= 378389)) return "4.5";

        // This code should never execute. A non-null release key should mean
        // that 4.5 or later is installed.
        return "No 4.5 or later version detected";
    }

    private static string GetVersionFromRegistry()
    {
        String maxDotNetVersion = "";
        // Opens the registry key for the .NET Framework entry.
        using (RegistryKey ndpKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, "")
                                        .OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
        {
            // As an alternative, if you know the computers you will query are running .NET Framework 4.5 
            // or later, you can use:
            // using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, 
            // RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
            foreach (string versionKeyName in ndpKey.GetSubKeyNames())
            {
                if (versionKeyName.StartsWith("v"))
                {
                    RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                    string name = (string)versionKey.GetValue("Version", "");
                    string sp = versionKey.GetValue("SP", "").ToString();
                    string install = versionKey.GetValue("Install", "").ToString();
                    if (install == "") //no install info, must be later.
                    {
                        Console.WriteLine(versionKeyName + "  " + name);
                        if (String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                    }
                    else
                    {
                        if (sp != "" && install == "1")
                        {
                            Console.WriteLine(versionKeyName + "  " + name + "  SP" + sp);
                            if (String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                        }

                    }
                    if (name != "")
                    {
                        continue;
                    }
                    foreach (string subKeyName in versionKey.GetSubKeyNames())
                    {
                        RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                        name = (string)subKey.GetValue("Version", "");
                        if (name != "")
                        {
                            sp = subKey.GetValue("SP", "").ToString();
                        }
                        install = subKey.GetValue("Install", "").ToString();
                        if (install == "")
                        {
                            //no install info, must be later.
                            Console.WriteLine(versionKeyName + "  " + name);
                            if (String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                        }
                        else
                        {
                            if (sp != "" && install == "1")
                            {
                                Console.WriteLine("  " + subKeyName + "  " + name + "  SP" + sp);
                                if (String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                            }
                            else if (install == "1")
                            {
                                Console.WriteLine("  " + subKeyName + "  " + name);
                                if (String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                            } // if
                        } // if
                    } // for
                } // if
            } // foreach
        } // using
        return maxDotNetVersion;
    }
    
} // class

在我的机器上，它输出：

v2.0.50727 2.0.50727.4927 SP2
v3.0 3.0.30729.4926 SP2
v3.5 3.5.30729.4926 SP1
v4
客户端4.7.03056
完整版 4.7.03056
v4.0
客户端4.0.0.0
.NET Framework 版本：4.7.2 或更高版本
**** 找到的最大 .NET 版本号是：4.7.2 或更高版本 ****

随着时间的推移，唯一需要维护的是内部版本号，一旦 .NET 版本大于 4.7.1 出现，这可以通过修改函数 CheckFor45PlusVersion 轻松完成，您需要知道新版本的发布密钥然后您可以添加它。 例如：

if (releaseKey >= 461308) return "4.7.1 or later";

此发行密钥仍然是最新的密钥，并且对 Windows 10 的 Fall Creators 更新有效。如果您仍在运行其他（较旧的）Windows 版本，则还有另一个密钥 >这个来自微软的文档：

.NET Framework 4.7.1 安装在所有其他 Windows 操作系统版本 461310 上

因此，如果您也需要它，则必须将

if (releaseKey >= 461310) return "4.7.1 or later";

CheckFor45PlusVersion 添加到函数顶部。
同样，它适用于较新的版本。 例如，我最近添加了4.8的检查。 您通常可以在 Microsoft 找到这些内部版本号。

---

注意：您不需要安装 Visual Studio，甚至不需要安装 PowerShell - 您可以使用 csc.exe 编译并运行上面的脚本，该脚本我已在此处进行了描述。

---

更新：问题是关于.NET Framework，为了完整起见，我还想提一下如何查询 .NET Core 的版本 - 与上面的相比，这很简单：打开命令 shell 并输入：

dotnet --info 输入

，它将列出 .NET Core 版本号、Windows 版本以及每个相关运行时 DLL 的版本。
示例输出：

.NET Core SDK（反映任何 global.json）：

  版本：2.1.300

  提交：adab45bf0c

运行时环境：

  操作系统名称：Windows

操作系统版本：10.0.15063

  操作系统平台：Windows

  RID：win10-x64

  基本路径：C:\Program Files\dotnet\sdk\2.1.300

主持人（对于支持有用）：

  版本：2.1.0

  提交：caa7b7e2ba

安装的 .NET Core SDK：

  1.1.9 [C:\Program Files\dotnet\sdk]

  2.1.102 [C:\Program Files\dotnet\sdk]

  ...

  2.1.300 [C:\Program Files\dotnet\sdk]

安装的 .NET Core 运行时：

  Microsoft.AspNetCore.All 2.1.0 [C:\Program
 Files\dotnet\shared\Microsoft.AspNetCore.All]

  ...

  Microsoft.NETCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

要安装其他 .NET Core 运行时或 SDK：

  https://aka.ms/dotnet-download

注意

• 如果您只需要版本号而不需要所有附加信息，则可以使用
  dotnet --version。

• 在 64 位 Windows PC 上，可以将 x86 版本与 x64 版本并排安装 .NET Core 版本。 如果是这种情况，您将只能获得环境变量PATH中第一个的版本。如果您需要保持最新并希望了解每个版本。 要查询两个版本，请使用：

C:\Program Files\dotnet\dotnet.exe --version
3.0.100-预览6-012264
C:\Program Files (x86)\dotnet\dotnet.exe --version
3.0.100-preview6-012264

在上面的示例中，两者是相同的，但如果您忘记更新两个实例，则可能会得到不同的结果！ 请注意，Program Files 适用于64 位 版本，Program Files (x86) 适用于32 位 版本。

---

更新：如果您更喜欢将内部版本号保留在列表中，而不是保留在一系列 if 语句中（如 Microsoft 建议的那样），那么您可以将此代码用于 CheckFor45PlusVersion反而：

private static string CheckFor45PlusVersion(int releaseKey)
{
    var release = new SortedDictionary<int, string>()
    {
            { 378389, "4.5" },
            { 378675, "4.5.1" }, { 379893, "4.5.2" },
            { 393295, "4.6" },
            { 394254, "4.6.1" }, { 394802, "4.6.2" },
            { 460798, "4.7" },
            { 461308, "4.7.1" }, { 461808, "4.7.2" },
            { 528040, "4.8 or later" }
    };
    int result = -1;
    foreach(var k in release)
    {
        if (k.Key <= releaseKey) result = k.Key; else break;
    };
    return (result > 0) ? release[result] : "No 4.5 or later version detected";
}

Answer 8

据我所知，框架中没有内置方法可以让您执行此操作。 您可以检查此 帖子 获取有关通过读取 Windows 注册表值确定框架版本的建议。

Answer 9

此类允许您的应用程序抛出一条优雅的通知消息，而不是在找不到正确的 .NET 版本时崩溃。 您需要做的就是在主代码中执行以下操作：

[STAThread]
static void Main(string[] args)
{
    if (!DotNetUtils.IsCompatible())
        return;
   . . .
}

默认情况下需要 4.5.2，但您可以根据自己的喜好进行调整，类（随意用 Console 替换 MessageBox）：

已更新为 4.8：

public class DotNetUtils
{
    public enum DotNetRelease
    {
        NOTFOUND,
        NET45,
        NET451,
        NET452,
        NET46,
        NET461,
        NET462,
        NET47,
        NET471,
        NET472,
        NET48,
    }

    public static bool IsCompatible(DotNetRelease req = DotNetRelease.NET452)
    {
        DotNetRelease r = GetRelease();
        if (r < req)
        {
            MessageBox.Show(String.Format("This this application requires {0} or greater.", req.ToString()));
            return false;
        }
        return true;
    }

    public static DotNetRelease GetRelease(int release = default(int))
    {
        int r = release != default(int) ? release : GetVersion();
        if (r >= 528040) return DotNetRelease.NET48;
        if (r >= 461808) return DotNetRelease.NET472;
        if (r >= 461308) return DotNetRelease.NET471;
        if (r >= 460798) return DotNetRelease.NET47;
        if (r >= 394802) return DotNetRelease.NET462;
        if (r >= 394254) return DotNetRelease.NET461;
        if (r >= 393295) return DotNetRelease.NET46;
        if (r >= 379893) return DotNetRelease.NET452;
        if (r >= 378675) return DotNetRelease.NET451;
        if (r >= 378389) return DotNetRelease.NET45;
        return DotNetRelease.NOTFOUND;
    }

    public static int GetVersion()
    {
        int release = 0;
        using (RegistryKey key = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32)
                                            .OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\"))
        {
            release = Convert.ToInt32(key.GetValue("Release"));
        }
        return release;
    }
}

当他们稍后添加新版本时可以轻松扩展。 在 4.5 之前我没有关心任何事情，但你明白了。

Answer 10

我试图将所有答案合并成一个整体。

使用：

NetFrameworkUtilities.GetVersion() 将返回 .NET Framework 当前可用的版本，如果不存在，则返回 null。

此示例适用于 .NET Framework 版本 3.5+。 它不需要管理员权限。

我想指出的是，您可以使用运算符 << 来检查版本。 和> 像这样：

var version = NetFrameworkUtilities.GetVersion();
if (version != null && version < new Version(4, 5))
{
    MessageBox.Show("Your .NET Framework version is less than 4.5");
}

代码：

using System;
using System.Linq;
using Microsoft.Win32;

namespace Utilities
{
    public static class NetFrameworkUtilities
    {
        public static Version GetVersion() => GetVersionHigher4() ?? GetVersionLowerOr4();

        private static Version GetVersionLowerOr4()
        {
            using (var key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP"))
            {
                var names = key?.GetSubKeyNames();

                //version names start with 'v', eg, 'v3.5' which needs to be trimmed off before conversion
                var text = names?.LastOrDefault()?.Remove(0, 1);
                if (string.IsNullOrEmpty(text))
                {
                    return null;
                }

                return text.Contains('.')
                    ? new Version(text)
                    : new Version(Convert.ToInt32(text), 0);
            }
        }

        private static Version GetVersionHigher4()
        {
            using (var key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full"))
            {
                var value = key?.GetValue("Release");
                if (value == null)
                {
                    return null;
                }

                // Checking the version using >= will enable forward compatibility,  
                // however you should always compile your code on newer versions of 
                // the framework to ensure your app works the same. 
                var releaseKey = Convert.ToInt32(value);
                if (releaseKey >= 528040) return new Version(4, 8, 0);
                if (releaseKey >= 461808) return new Version(4, 7, 2);
                if (releaseKey >= 461308) return new Version(4, 7, 1);
                if (releaseKey >= 460798) return new Version(4, 7);
                if (releaseKey >= 394747) return new Version(4, 6, 2);
                if (releaseKey >= 394254) return new Version(4, 6, 1);
                if (releaseKey >= 381029) return new Version(4, 6);
                if (releaseKey >= 379893) return new Version(4, 5, 2);
                if (releaseKey >= 378675) return new Version(4, 5, 1);
                if (releaseKey >= 378389) return new Version(4, 5);

                // This line should never execute. A non-null release key should mean 
                // that 4.5 or later is installed. 
                return new Version(4, 5);
            }
        }
    }
}

Answer 11

public class DA
{
    public static class VersionNetFramework
    {
        public static string GetVersion()
        {
            return Environment.Version.ToString();
        }
        public static string GetVersionDicription()
        {
            int Major = Environment.Version.Major;
            int Minor = Environment.Version.Minor;
            int Build = Environment.Version.Build;
            int Revision = Environment.Version.Revision;

            //http://dzaebel.net/NetVersionen.htm
            //http://stackoverflow.com/questions/12971881/how-to-reliably-detect-the-actual-net-4-5-version-installed

            //4.0.30319.42000 = .NET 4.6 on Windows 8.1 64 - bit
            if ((Major >=4) && (Minor >=0) && (Build >= 30319) && (Revision >= 42000))
                return @".NET 4.6 on Windows 8.1 64 - bit or later";
            //4.0.30319.34209 = .NET 4.5.2 on Windows 8.1 64 - bit
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 34209))
                return @".NET 4.5.2 on Windows 8.1 64 - bit or later";
            //4.0.30319.34209 = .NET 4.5.2 on Windows 7 SP1 64 - bit
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 34209))
                return @".NET 4.5.2 on Windows 7 SP1 64 - bit or later";
            //4.0.30319.34014 = .NET 4.5.1 on Windows 8.1 64 - bit
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 34014))
                return @".NET 4.5.1 on Windows 8.1 64 - bit or later";
            //4.0.30319.18444 = .NET 4.5.1 on Windows 7 SP1 64 - bit(with MS14 - 009 security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 18444))
                return @".NET 4.5.1 on Windows 7 SP1 64 - bit(with MS14 - 009 security update) or later";
            //4.0.30319.18408 = .NET 4.5.1 on Windows 7 SP1 64 - bit
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 18408))
                return @".NET 4.5.1 on Windows 7 SP1 64 - bit or later";
            //4.0.30319.18063 = .NET 4.5 on Windows 7 SP1 64 - bit(with MS14 - 009 security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 18063))
                return @".NET 4.5 on Windows 7 SP1 64 - bit(with MS14 - 009 security update) or later";
            //4.0.30319.18052 = .NET 4.5 on Windows 7 SP1 64 - bit
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 18052))
                return @".NET 4.5 on Windows 7 SP1 64 - bit or later";
            //4.0.30319.18010 = .NET 4.5 on Windows 8
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 18010))
                return @".NET 4.5 on Windows 8 or later";
            //4.0.30319.17929 = .NET 4.5 RTM
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 17929))
                return @".NET 4.5 RTM or later";
            //4.0.30319.17626 = .NET 4.5 RC
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 17626))
                return @".NET 4.5 RC or later";
            //4.0.30319.17020.NET 4.5 Preview, September 2011
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 17020))
                return @".NET 4.5 Preview, September 2011 or later";
            //4.0.30319.2034 = .NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS14 - 009 LDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 2034))
                return @".NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS14 - 009 LDR security update) or later";
            //4.0.30319.1026 = .NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS14 - 057 GDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 1026))
                return @".NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS14 - 057 GDR security update) or later";
            //4.0.30319.1022 = .NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS14 - 009 GDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 1022))
                return @".NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS14 - 009 GDR security update) or later";
            //4.0.30319.1008 = .NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS13 - 052 GDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 1008))
                return @".NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS13 - 052 GDR security update) or later";
            //4.0.30319.544 = .NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS12 - 035 LDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 544))
                return @".NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS12 - 035 LDR security update) or later";
            //4.0.30319.447   yes built by: RTMLDR, .NET 4.0 Platform Update 1, April 2011
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 447))
                return @"built by: RTMLDR, .NET 4.0 Platform Update 1, April 2011 or later";
            //4.0.30319.431   yes built by: RTMLDR, .NET 4.0 GDR Update, March 2011 / with VS 2010 SP1 / or.NET 4.0 Update
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 431))
                return @"built by: RTMLDR, .NET 4.0 GDR Update, March 2011 / with VS 2010 SP1 / or.NET 4.0 Update or later";
            //4.0.30319.296 = .NET 4.0 on Windows XP SP3, 7(with MS12 - 074 GDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 296))
                return @".NET 4.0 on Windows XP SP3, 7(with MS12 - 074 GDR security update) or later";
            //4.0.30319.276 = .NET 4.0 on Windows XP SP3 (4.0.3 Runtime update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 276))
                return @".NET 4.0 on Windows XP SP3 (4.0.3 Runtime update) or later";
            //4.0.30319.269 = .NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS12 - 035 GDR security update)
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 269))
                return @".NET 4.0 on Windows XP SP3, 7, 7 SP1(with MS12 - 035 GDR security update) or later";
            //4.0.30319.1 yes built by: RTMRel, .NET 4.0 RTM Release, April 2010
            if ((Major >= 4) && (Minor >= 0) && (Build >= 30319) && (Revision >= 1))
                return @"built by: RTMRel, .NET 4.0 RTM Release, April 2010 or later";

            //4.0.30128.1     built by: RC1Rel, .NET 4.0 Release Candidate, Feb 2010
            if ((Major >=4) && (Minor >=0) && (Build >= 30128) && (Revision >= 1))
                return @"built by: RC1Rel, .NET 4.0 Release Candidate, Feb 2010 or later";
            //4.0.21006.1     built by: B2Rel, .NET 4.0 Beta2, Oct 2009
            if ((Major >=4) && (Minor >=0) && (Build >= 21006) && (Revision >=1))
                return @"built by: B2Rel, .NET 4.0 Beta2, Oct 2009 or later";
            //4.0.20506.1     built by: Beta1, .NET 4.0 Beta1, May 2009
            if ((Major >=4) && (Minor >=0) && (Build >= 20506) && (Revision >=1))
                return @"built by: Beta1, .NET 4.0 Beta1, May 2009 or later";
            //4.0.11001.1     built by: CTP2 VPC, .NET 4.0 CTP, October 2008
            if ((Major >=4) && (Minor >=0) && (Build >= 11001) && (Revision >=1))
                return @"built by: CTP2 VPC, .NET 4.0 CTP, October 2008 or later";

            //3.5.30729.5420  yes built by: Win7SP1, .NET 3.5.1 Sicherheits - Update, 12 April 2011
            if ((Major >=3) && (Minor >=5) && (Build >= 30729) && (Revision >= 5420))
                return @"built by: Win7SP1, .NET 3.5.1 Sicherheits - Update, 12 April 2011 or later";
            //3.5.30729.5004  yes built by: NetFXw7 / Windows 7..Rel., Jan 2010 / +Data functions KB976127 .NET 3.5 SP1
            if ((Major >=3) && (Minor >=5) && (Build >= 30729) && (Revision >= 5004))
                return @"built by: NetFXw7 / Windows 7..Rel., Jan 2010 / +Data functions KB976127 .NET 3.5 SP1 or later";
            //3.5.30729.4466  yes built by: NetFXw7 / Windows XP..Rel. , Jan 2010 / +Data functions KB976127 .NET 3.5 SP1
            if ((Major >=3) && (Minor >=5) && (Build >= 30729) && (Revision >= 4466))
                return @"built by: NetFXw7 / Windows XP..Rel. , Jan 2010 / +Data functions KB976127 .NET 3.5 SP1 or later";
            //3.5.30729.4926  yes built by: NetFXw7 / Windows 7 Release, Oct 2009 / .NET 3.5 SP1 + Hotfixes
            if ((Major >=3) && (Minor >=5) && (Build >= 30729) && (Revision >= 4926))
                return @"built by: NetFXw7 / Windows 7 Release, Oct 2009 / .NET 3.5 SP1 + Hotfixes or later";
            //3.5.30729.4918      built by: NetFXw7 / Windows 7 Release Candidate, June 2009
            if ((Major >=3) && (Minor >=5) && (Build >= 30729) && (Revision >= 4918))
                return @"built by: NetFXw7 / Windows 7 Release Candidate, June 2009 or later";
            //3.5.30729.196   yes built by: QFE, .NET 3.5 Family Update Vista / W2008, Dec 2008
            if ((Major >= 3) && (Minor >= 5) && (Build >= 30729) && (Revision >=196))
                return @"built by: QFE, .NET 3.5 Family Update Vista / W2008, Dec 2008 or later";
            //3.5.30729.1 yes built by: SP, .NET 3.5 SP1, Aug 2008
            if ((Major >= 3) && (Minor >= 5) && (Build >= 30729) && (Revision >=1))
                return @"built by: SP, .NET 3.5 SP1, Aug 2008 or later";

            //3.5.30428.1         built by: SP1Beta1, .NET 3.5 SP1 BETA1, May 2008
            if ((Major >=3) && (Minor >=5) && (Build >= 30428) && (Revision >=1))
                return @"built by: SP1Beta1, .NET 3.5 SP1 BETA1, May 2008 or later";
            //3.5.21022.8 yes built by: RTM, Jan 2008
            if ((Major >=3) && (Minor >=5) && (Build >= 21022) && (Revision >= 8))
                return @"built by: RTM, Jan 2008 or later";
            //3.5.20706.1     built by: Beta2, Orcas Beta2, Oct 2007
            if ((Major >=3) && (Minor >=5) && (Build >= 20706) && (Revision >= 1))
                return @"built by: Beta2, Orcas Beta2, Oct 2007 or later";
            //3.5.20526.0     built by: MCritCTP, Orcas Beta1, Mar 2007
            if ((Major >=3) && (Minor >=5) && (Build >= 20526) && (Revision >=0))
                return @"built by: MCritCTP, Orcas Beta1, Mar 2007 or later";

            //3.0.6920.1500   yes built by: QFE, Family Update Vista / W2008, Dez 2008, KB958483
            if ((Major >=3) && (Minor >=0) && (Build >= 6920) && (Revision >= 1500))
                return @"built by: QFE, Family Update Vista / W2008, Dez 2008, KB958483 or later";
            //3.0.4506.4926   yes(NetFXw7.030729 - 4900) / Windows 7 Release, Oct 2009
            if ((Major >=3) && (Minor >=0) && (Build >= 4506) && (Revision >= 4926))
                return @"(NetFXw7.030729 - 4900) / Windows 7 Release, Oct 2009 or later";
            //3.0.4506.4918(NetFXw7.030729 - 4900) / Windows 7 Release Candidate, June 2009
            if ((Major >=3) && (Minor >=5) && (Build >= 4506) && (Revision >= 4918))
                return @"(NetFXw7.030729 - 4900) / Windows 7 Release Candidate, June 2009 or later";
            //3.0.4506.2152       3.0.4506.2152(SP.030729 - 0100) / .NET 4.0 Beta1 / May 2009
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 2152))
                return @"3.0.4506.2152(SP.030729 - 0100) / .NET 4.0 Beta1 / May 2009 or later";
            //3.0.4506.2123   yes(NetFX.030618 - 0000).NET 3.0 SP2, Aug 2008
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 2123))
                return @"s(NetFX.030618 - 0000).NET 3.0 SP2, Aug 2008 or later";
            //3.0.4506.2062(SP1Beta1.030428 - 0100), .NET 3.0 SP1 BETA1, May 2008
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 2062))
                return @"(SP1Beta1.030428 - 0100), .NET 3.0 SP1 BETA1, May 2008 or later";
            //3.0.4506.590(winfxredb2.004506 - 0590), Orcas Beta2, Oct 2007
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 590))
                return @"(winfxredb2.004506 - 0590), Orcas Beta2, Oct 2007 or later";
            //3.0.4506.577(winfxred.004506 - 0577), Orcas Beta1, Mar 2007
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 577))
                return @"(winfxred.004506 - 0577), Orcas Beta1, Mar 2007 or later";
            //3.0.4506.30 yes Release (.NET Framework 3.0) Nov 2006
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 30))
                return @"Release (.NET Framework 3.0) Nov 2006 or later";
            //3.0.4506.25 yes(WAPRTM.004506 - 0026) Vista Ultimate, Jan 2007
            if ((Major >= 3) && (Minor >= 5) && (Build >= 4506) && (Revision >= 25))
                return @"(WAPRTM.004506 - 0026) Vista Ultimate, Jan 2007 or later";

            //2.0.50727.4927  yes(NetFXspW7.050727 - 4900) / Windows 7 Release, Oct 2009
            if ((Major >=2) && (Minor >=0) && (Build >= 50727) && (Revision >= 4927))
                return @"(NetFXspW7.050727 - 4900) / Windows 7 Release, Oct 2009 or later";
            //2.0.50727.4918(NetFXspW7.050727 - 4900) / Windows 7 Release Candidate, June 2009
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 4918))
                return @"(NetFXspW7.050727 - 4900) / Windows 7 Release Candidate, June 2009 or later";
            //2.0.50727.4200  yes(NetFxQFE.050727 - 4200).NET 2.0 SP2, KB974470, Securityupdate, Oct 2009
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 4200))
                return @"(NetFxQFE.050727 - 4200).NET 2.0 SP2, KB974470, Securityupdate, Oct 2009 or later";
            //2.0.50727.3603(GDR.050727 - 3600).NET 4.0 Beta 2, Oct 2009
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 3603))
                return @"(GDR.050727 - 3600).NET 4.0 Beta 2, Oct 2009 or later";
            //2.0.50727.3082  yes(QFE.050727 - 3000), .NET 3.5 Family Update XP / W2003, Dez 2008, KB958481
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 3082))
                return @"(QFE.050727 - 3000), .NET 3.5 Family Update XP / W2003, Dez 2008, KB958481 or later";
            //2.0.50727.3074  yes(QFE.050727 - 3000), .NET 3.5 Family Update Vista / W2008, Dez 2008, KB958481
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 3074))
                return @"(QFE.050727 - 3000), .NET 3.5 Family Update Vista / W2008, Dez 2008, KB958481 or later";
            //2.0.50727.3053  yes(netfxsp.050727 - 3000), .NET 2.0 SP2, Aug 2008
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 3053))
                return @"yes(netfxsp.050727 - 3000), .NET 2.0 SP2, Aug 2008 or later";
            //2.0.50727.3031(netfxsp.050727 - 3000), .NET 2.0 SP2 Beta 1, May 2008
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 3031))
                return @"(netfxsp.050727 - 3000), .NET 2.0 SP2 Beta 1, May 2008 or later";
            //2.0.50727.1434  yes(REDBITS.050727 - 1400), Windows Server 2008 and Windows Vista SP1, Dez 2007
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 1434))
                return @"(REDBITS.050727 - 1400), Windows Server 2008 and Windows Vista SP1, Dez 2007 or later";
            //2.0.50727.1433  yes(REDBITS.050727 - 1400), .NET 2.0 SP1 Release, Nov 2007, http://www.microsoft.com/downloads/details.aspx?FamilyID=79bc3b77-e02c-4ad3-aacf-a7633f706ba5
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 1433))
                return @"(REDBITS.050727 - 1400), .NET 2.0 SP1 Release, Nov 2007 or later";
            //2.0.50727.1378(REDBITSB2.050727 - 1300), Orcas Beta2, Oct 2007
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 1378))
                return @"(REDBITSB2.050727 - 1300), Orcas Beta2, Oct 2007 or later";
            //2.0.50727.1366(REDBITS.050727 - 1300), Orcas Beta1, Mar 2007
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 1366))
                return @"(REDBITS.050727 - 1300), Orcas Beta1, Mar 2007 or later";
            //2.0.50727.867   yes(VS Express Edition 2005 SP1), Apr 2007, http://www.microsoft.com/downloads/details.aspx?FamilyId=7B0B0339-613A-46E6-AB4D-080D4D4A8C4E
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 867))
                return @"(VS Express Edition 2005 SP1), Apr 2007 or later";
            //2.0.50727.832(Fix x86 VC++2005), Apr 2007, http://support.microsoft.com/kb/934586/en-us
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 832))
                return @"(Fix x86 VC++2005), Apr 2007 or later";
            //2.0.50727.762   yes(VS TeamSuite SP1), http://www.microsoft.com/downloads/details.aspx?FamilyId=BB4A75AB-E2D4-4C96-B39D-37BAF6B5B1DC
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 762))
                return @"(VS TeamSuite SP1) or later";
            //2.0.50727.312   yes(rtmLHS.050727 - 3100) Vista Ultimate, Jan 2007
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 312))
                return @"(rtmLHS.050727 - 3100) Vista Ultimate, Jan 2007 or later";
            //2.0.50727.42    yes Release (.NET Framework 2.0) Oct 2005
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 42))
                return @"Release (.NET Framework 2.0) Oct 2005 or later";
            //2.0.50727.26        Version 2.0(Visual Studio Team System 2005 Release Candidate) Oct 2005
            if ((Major >= 2) && (Minor >= 0) && (Build >= 50727) && (Revision >= 26))
                return @"Version 2.0(Visual Studio Team System 2005 Release Candidate) Oct 2005 or later";

            //2.0.50712       Version 2.0(Visual Studio Team System 2005(Drop3) CTP) July 2005
            if ((Major >=2) && (Minor >=0) && (Build >= 50712))
                return @"Version 2.0(Visual Studio Team System 2005(Drop3) CTP) July 2005 or later";
            //2.0.50215       Version 2.0(WinFX SDK for Indigo / Avalon 2005 CTP) July 2005
            if ((Major >=2) && (Minor >=0) && (Build >= 50215))
                return @"Version 2.0(WinFX SDK for Indigo / Avalon 2005 CTP) July 2005 or later";
            //2.0.50601.0     Version 2.0(Visual Studio.NET 2005 CTP) June 2005
            if ((Major >=2) && (Minor >=0) && (Build >= 50601) && (Revision >=0))
                return @"Version 2.0(Visual Studio.NET 2005 CTP) June 2005 or later";
            //2.0.50215.44        Version 2.0(Visual Studio.NET 2005 Beta 2, Visual Studio Express Beta 2) Apr 2005
            if ((Major >=2) && (Minor >=0) && (Build >= 50215) && (Revision >= 44))
                return @"Version 2.0(Visual Studio.NET 2005 Beta 2, Visual Studio Express Beta 2) Apr 2005 or later";
            //2.0.50110.28        Version 2.0(Visual Studio.NET 2005 CTP, Professional Edition) Feb 2005
            if ((Major >=2) && (Minor >=0) && (Build >= 50110) && (Revision >=28))
                return @"Version 2.0(Visual Studio.NET 2005 CTP, Professional Edition) Feb 2005 or later";
            //2.0.41115.19        Version 2.0(Visual Studio.NET 2005 Beta 1, Team System Refresh) Dec 2004
            if ((Major >=2 ) && (Minor >=0 ) && (Build >= 41115) && (Revision >= 19))
                return @"Version 2.0(Visual Studio.NET 2005 Beta 1, Team System Refresh) Dec 2004 or later";
            //2.0.40903.0         Version 2.0(Whidbey CTP, Visual Studio Express) Oct 2004
            if ((Major >=2) && (Minor >=0) && (Build >= 40903) && (Revision >=0))
                return @"Version 2.0(Whidbey CTP, Visual Studio Express) Oct 2004 or later";
            //2.0.40607.85        Version 2.0(Visual Studio.NET 2005 Beta 1, Team System Refresh) Aug 2004 *
            if ((Major >=2) && (Minor >=0) && (Build >= 40607) && (Revision >= 85))
                return @"Version 2.0(Visual Studio.NET 2005 Beta 1, Team System Refresh) Aug 2004 * or later";
            //2.0.40607.42        Version 2.0(SQL Server Yukon Beta 2) July 2004
            if ((Major >=2) && (Minor >=0) && (Build >= 40607) && (Revision >= 42))
                return @"Version 2.0(SQL Server Yukon Beta 2) July 2004 or later";
            //2.0.40607.16        Version 2.0(Visual Studio.NET 2005 Beta 1, TechEd Europe 2004) June 2004
            if ((Major >=2) && (Minor >=0) && (Build >= 40607) && (Revision >= 16))
                return @"Version 2.0(Visual Studio.NET 2005 Beta 1, TechEd Europe 2004) June 2004 or later";
            //2.0.40301.9         Version 2.0(Whidbey CTP, WinHEC 2004) March 2004 *
            if ((Major >=0) && (Minor >=0) && (Build >= 40301) && (Revision >=9))
                return @"Version 2.0(Whidbey CTP, WinHEC 2004) March 2004 * or later";

            //1.2.30703.27        Version 1.2(Whidbey Alpha, PDC 2004) Nov 2003 *
            if ((Major >=1) && (Minor >=2) && (Build >= 30703) && (Revision >= 27))
                return @"Version 1.2(Whidbey Alpha, PDC 2004) Nov 2003 * or later";
            //1.2.21213.1     Version 1.2(Whidbey pre - Alpha build) *
            if ((Major >=1) && (Minor >=2) && (Build >= 21213) && (Revision >=1))
                return @"Version 1.2(Whidbey pre - Alpha build) * or later";

            //1.1.4322.2443   yes Version 1.1 Servicepack 1, KB953297, Oct 2009
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >=2443))
                return @"Version 1.1 Servicepack 1, KB953297, Oct 2009 or later";
            //1.1.4322.2407   yes Version 1.1 RTM
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >= 2407))
                return @"Version 1.1 RTM or later";
            //1.1.4322.2407       Version 1.1 Orcas Beta2, Oct 2007
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >= 2407))
                return @"Version 1.1 Orcas Beta2, Oct 2007 or later";
            //1.1.4322.2379       Version 1.1 Orcas Beta1, Mar 2007
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >= 2379))
                return @"Version 1.1 Orcas Beta1, Mar 2007 or later";
            //1.1.4322.2032   yes Version 1.1 SP1 Aug 2004
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >= 2032))
                return @"Version 1.1 SP1 Aug 2004 or later";
            //1.1.4322.573    yes Version 1.1 RTM(Visual Studio.NET 2003 / Windows Server 2003) Feb 2003 *
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >= 573))
                return @"Version 1.1 RTM(Visual Studio.NET 2003 / Windows Server 2003) Feb 2003 * or later";
            //1.1.4322.510        Version 1.1 Final Beta Oct 2002 *
            if ((Major >=1) && (Minor >=1) && (Build >= 4322) && (Revision >= 510))
                return @"Version 1.1 Final Beta Oct 2002 * or later";

            //1.0.3705.6018   yes Version 1.0 SP3 Aug 2004
            if ((Major >=1) && (Minor >=0) && (Build >= 3705) && (Revision >= 6018))
                return @"Version 1.0 SP3 Aug 2004 or later";
            //1.0.3705.288    yes Version 1.0 SP2 Aug 2002 *
            if ((Major >=1) && (Minor >=0) && (Build >= 3705) && (Revision >= 288))
                return @"Version 1.0 SP2 Aug 2002 * or later";
            //1.0.3705.209    yes Version 1.0 SP1 Mar 2002 *
            if ((Major >=1) && (Minor >=0) && (Build >= 3705) && (Revision >=209))
                return @"Version 1.0 SP1 Mar 2002 * or later";
            //1.0.3705.0  yes Version 1.0 RTM(Visual Studio.NET 2002) Feb 2002 *
            if ((Major >=1) && (Minor >=0) && (Build >= 3705) && (Revision >=0))
                return @"Version 1.0 RTM(Visual Studio.NET 2002) Feb 2002 * or later";
            //1.0.3512.0      Version 1.0 Pre - release RC3(Visual Studio.NET 2002 RC3)
            if ((Major >=1) && (Minor >=0) && (Build >= 3512) && (Revision >=0))
                return @"Version 1.0 Pre - release RC3(Visual Studio.NET 2002 RC3) or later";
            //1.0.2914.16     Version 1.0 Public Beta 2 Jun 2001 *
            if ((Major >=1) && (Minor >=0) && (Build >= 2914) && (Revision >= 16))
                return @"Version 1.0 Public Beta 2 Jun 2001 * or later";
            //1.0.2204.21         Version 1.0 Public Beta 1 Nov 2000 *
            if ((Major >=1) && (Minor >=0) && (Build >= 2204) && (Revision >=21))
                return @"Version 1.0 Public Beta 1 Nov 2000 * or later";

            return @"Unknown .NET version";
        }
    }
}

Answer 12

System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription

属性返回运行应用程序的 .NET 安装的名称：

public static string FrameworkDescription { get; }

它返回 .NET 5 控制台应用程序上的值“.NET 5.0.3”。

来自 Microsoft 的更多信息：

System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription 属性

Answer 13

感谢您的这篇文章非常有用。
我必须稍微调整一下才能检查框架 2.0，因为注册表项无法直接转换为双精度。 这是代码：

string[] version_names = rk.GetSubKeyNames();
//version names start with 'v', eg, 'v3.5'
//we also need to take care of strings like v2.0.50727...
string sCurrent = version_names[version_names.Length - 1].Remove(0, 1);
if (sCurrent.LastIndexOf(".") > 1)
{
    string[] sSplit = sCurrent.Split('.');
    sCurrent = sSplit[0] + "." + sSplit[1] + sSplit[2];
}
double dCurrent = Convert.ToDouble(sCurrent, System.Globalization.CultureInfo.InvariantCulture);
double dExpected = Convert.ToDouble(sExpectedVersion);
if (dCurrent >= dExpected)

Answer 14

public class DA {
  public static class VersionNetFramework {
    public static string Get45or451FromRegistry()
    {//https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx
        using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\"))
        {
            int releaseKey = Convert.ToInt32(ndpKey.GetValue("Release"));
            if (true)
            {
                return (@"Version: " + CheckFor45DotVersion(releaseKey));
            }
        }
    }
    // Checking the version using >= will enable forward compatibility, 
    // however you should always compile your code on newer versions of
    // the framework to ensure your app works the same.
    private static string CheckFor45DotVersion(int releaseKey)
    {//https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx
        if (releaseKey >= 394271)
            return "4.6.1 installed on all other Windows OS versions or later";
        if (releaseKey >= 394254)
            return "4.6.1 installed on Windows 10 or later";
        if (releaseKey >= 393297)
            return "4.6 installed on all other Windows OS versions or later";
        if (releaseKey >= 393295)
            return "4.6 installed with Windows 10 or later";
        if (releaseKey >= 379893)
            return "4.5.2 or later";
        if (releaseKey >= 378758)
            return "4.5.1 installed on Windows 8, Windows 7 SP1, or Windows Vista SP2 or later";
        if (releaseKey >= 378675)
            return "4.5.1 installed with Windows 8.1 or later";
        if (releaseKey >= 378389)
            return "4.5 or later";

        return "No 4.5 or later version detected";
    }
    public static string GetVersionFromRegistry()
    {//https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx
        string res = @"";
        // Opens the registry key for the .NET Framework entry.
        using (RegistryKey ndpKey =
            RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, "").
            OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
        {
            // As an alternative, if you know the computers you will query are running .NET Framework 4.5 
            // or later, you can use:
            // using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, 
            // RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
            foreach (string versionKeyName in ndpKey.GetSubKeyNames())
            {
                if (versionKeyName.StartsWith("v"))
                {

                    RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                    string name = (string)versionKey.GetValue("Version", "");
                    string sp = versionKey.GetValue("SP", "").ToString();
                    string install = versionKey.GetValue("Install", "").ToString();
                    if (install == "") //no install info, must be later.
                        res += (versionKeyName + "  " + name) + Environment.NewLine;
                    else
                    {
                        if (sp != "" && install == "1")
                        {
                            res += (versionKeyName + "  " + name + "  SP" + sp) + Environment.NewLine;
                        }

                    }
                    if (name != "")
                    {
                        continue;
                    }
                    foreach (string subKeyName in versionKey.GetSubKeyNames())
                    {
                        RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                        name = (string)subKey.GetValue("Version", "");
                        if (name != "")
                            sp = subKey.GetValue("SP", "").ToString();
                        install = subKey.GetValue("Install", "").ToString();
                        if (install == "") //no install info, must be later.
                            res += (versionKeyName + "  " + name) + Environment.NewLine;
                        else
                        {
                            if (sp != "" && install == "1")
                            {
                                res += ("  " + subKeyName + "  " + name + "  SP" + sp) + Environment.NewLine;
                            }
                            else if (install == "1")
                            {
                                res += ("  " + subKeyName + "  " + name) + Environment.NewLine;
                            }
                        }
                    }
                }
            }
        }
        return res;
    }
    public static string GetUpdateHistory()
    {//https://msdn.microsoft.com/en-us/library/hh925567(v=vs.110).aspx
        string res=@"";
        using (RegistryKey baseKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\Updates"))
        {
            foreach (string baseKeyName in baseKey.GetSubKeyNames())
            {
                if (baseKeyName.Contains(".NET Framework") || baseKeyName.StartsWith("KB") || baseKeyName.Contains(".NETFramework"))
                {

                    using (RegistryKey updateKey = baseKey.OpenSubKey(baseKeyName))
                    {
                        string name = (string)updateKey.GetValue("PackageName", "");
                        res += baseKeyName + "  " + name + Environment.NewLine;
                        foreach (string kbKeyName in updateKey.GetSubKeyNames())
                        {
                            using (RegistryKey kbKey = updateKey.OpenSubKey(kbKeyName))
                            {
                                name = (string)kbKey.GetValue("PackageName", "");
                                res += ("  " + kbKeyName + "  " + name) + Environment.NewLine;

                                if (kbKey.SubKeyCount > 0)
                                {
                                    foreach (string sbKeyName in kbKey.GetSubKeyNames())
                                    {
                                        using (RegistryKey sbSubKey = kbKey.OpenSubKey(sbKeyName))
                                        {
                                            name = (string)sbSubKey.GetValue("PackageName", "");
                                            if (name == "")
                                                name = (string)sbSubKey.GetValue("Description", "");
                                            res += ("    " + sbKeyName + "  " + name) + Environment.NewLine;
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
        return res;
    }
}

使用类 DA.VersionNetFramework

private void Form1_Shown(object sender, EventArgs e)
{
    //
    // Current OS Information
    //
    richTextBox1.Text = @"Current OS Information:";
    richTextBox1.AppendText(Environment.NewLine +
                            "Machine Name: " + Environment.MachineName);
    richTextBox1.AppendText(Environment.NewLine +
                            "Platform: " + Environment.OSVersion.Platform.ToString());
    richTextBox1.AppendText(Environment.NewLine +
                            Environment.OSVersion);
    //
    // .NET Framework Environment Information
    //
    richTextBox1.AppendText(Environment.NewLine + Environment.NewLine +
                                       ".NET Framework Environment Information:");
    richTextBox1.AppendText(Environment.NewLine +
                            "Environment.Version " + Environment.Version);
    richTextBox1.AppendText(Environment.NewLine + 
                            DA.VersionNetFramework.GetVersionDicription());
    //
    // .NET Framework Information From Registry
    //
    richTextBox1.AppendText(Environment.NewLine + Environment.NewLine +
                                       ".NET Framework Information From Registry:");
    richTextBox1.AppendText(Environment.NewLine +
                            DA.VersionNetFramework.GetVersionFromRegistry());
    //
    // .NET Framework 4.5 or later Information From Registry
    //
    richTextBox1.AppendText(Environment.NewLine + 
                                       ".NET Framework 4.5 or later Information From Registry:");
    richTextBox1.AppendText(Environment.NewLine +
                            DA.VersionNetFramework.Get45or451FromRegistry());
    //
    // Update History
    //
    richTextBox1.AppendText(Environment.NewLine + Environment.NewLine +
                            "Update History");
    richTextBox1.AppendText(Environment.NewLine + 
                            DA.VersionNetFramework.GetUpdateHistory());
    //
    // Setting Cursor to first character of textbox
    //
    if (!richTextBox1.Text.Equals(""))
    {
        richTextBox1.SelectionStart = 1;
    }
}

结果：

当前操作系统信息：
机器名称：D1
平台：Win32NT
Microsoft Windows NT 6.2.9200.0

.NET Framework 环境信息：
环境.版本4.0.30319.42000
Windows 8.1 64 位或更高版本上的 .NET 4.6

来自注册表的 .NET Framework 信息：
v2.0.50727 2.0.50727.4927 SP2
v3.0 3.0.30729.4926 SP2
v3.5 3.5.30729.4926 SP1

v4
客户端4.6.00079
完整版 4.6.00079
v4.0
客户端 4.0.0.0

.NET Framework 4.5 或更高版本 来自注册表的信息：
版本：4.6随Windows 10或更高版本安装

更新历史记录
Microsoft .NET Framework 4 客户端配置文件
KB2468871
KB2468871v2
KB2478063
KB2533523
KB2544514
KB2600211
KB2600217
Microsoft .NET Framework 4 扩展
KB2468871
KB2468871v2
KB2478063
KB2533523
KB2544514
KB2600211
KB2600217
Microsoft .NET Framework 4 多目标包
(KB2504637) 的 KB2504637 更新

Answer 15

我更改了 Matt 的类，以便可以在任何项目中重用它，而无需在控制台上打印所有检查并返回安装了正确的最大版本的简单字符串。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Win32;

namespace MyNamespace
{
    public class DotNetVersion
    {
        protected bool printVerification;

        public DotNetVersion(){
            this.printVerification=false;
        }
        public DotNetVersion(bool printVerification){
            this.printVerification=printVerification;
        }


        public string getDotNetVersion(){
            string maxDotNetVersion = getVersionFromRegistry();
            if(String.Compare(maxDotNetVersion, "4.5") >= 0){
                string v45Plus = get45PlusFromRegistry();
                if(!string.IsNullOrWhiteSpace(v45Plus)) maxDotNetVersion = v45Plus;
            }
            log("*** Maximum .NET version number found is: " + maxDotNetVersion + "***");

            return maxDotNetVersion;
        }

        protected string get45PlusFromRegistry(){
            String dotNetVersion = "";
            const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";
            using(RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey)){
                if(ndpKey != null && ndpKey.GetValue("Release") != null){
                    dotNetVersion = checkFor45PlusVersion((int)ndpKey.GetValue("Release"));
                    log(".NET Framework Version: " + dotNetVersion);
                }else{
                    log(".NET Framework Version 4.5 or later is not detected.");
                }
            }
            return dotNetVersion;
        }

        // Checking the version using >= will enable forward compatibility.
        protected string checkFor45PlusVersion(int releaseKey){
            if(releaseKey >= 461308) return "4.7.1 or later";
            if(releaseKey >= 460798) return "4.7";
            if(releaseKey >= 394802) return "4.6.2";
            if(releaseKey >= 394254) return "4.6.1";
            if(releaseKey >= 393295) return "4.6";
            if((releaseKey >= 379893)) return "4.5.2";
            if((releaseKey >= 378675)) return "4.5.1";
            if((releaseKey >= 378389)) return "4.5";

            // This code should never execute. A non-null release key should mean
            // that 4.5 or later is installed.
            log("No 4.5 or later version detected");
            return "";
        }

        protected string getVersionFromRegistry(){
            String maxDotNetVersion = "";
            // Opens the registry key for the .NET Framework entry.
            using(RegistryKey ndpKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, "")
                                            .OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\")){
                // As an alternative, if you know the computers you will query are running .NET Framework 4.5 
                // or later, you can use:
                // using(RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, 
                // RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
                string[] subKeyNnames = ndpKey.GetSubKeyNames();
                foreach(string versionKeyName in subKeyNnames){
                    if(versionKeyName.StartsWith("v")){
                        RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                        string name =(string)versionKey.GetValue("Version", "");
                        string sp = versionKey.GetValue("SP", "").ToString();
                        string install = versionKey.GetValue("Install", "").ToString();
                        if(string.IsNullOrWhiteSpace(install)){ //no install info, must be later.
                            log(versionKeyName + "  " + name);
                            if(String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                        }else{
                            if(!string.IsNullOrWhiteSpace(sp) && "1".Equals(install)){
                                log(versionKeyName + "  " + name + "  SP" + sp);
                                if(String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                            }

                        }
                        if(!string.IsNullOrWhiteSpace(name)){
                            continue;
                        }

                        string[] subKeyNames = versionKey.GetSubKeyNames();
                        foreach(string subKeyName in subKeyNames){
                            RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                            name =(string)subKey.GetValue("Version", "");
                            if(!string.IsNullOrWhiteSpace(name)){
                                sp = subKey.GetValue("SP", "").ToString();
                            }
                            install = subKey.GetValue("Install", "").ToString();
                            if(string.IsNullOrWhiteSpace(install)){
                                //no install info, must be later.
                                log(versionKeyName + "  " + name);
                                if(String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                            }else{
                                if(!string.IsNullOrWhiteSpace(sp) && "1".Equals(install)){
                                    log("  " + subKeyName + "  " + name + "  SP" + sp);
                                    if(String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                                }
                                else if("1".Equals(install)){
                                    log("  " + subKeyName + "  " + name);
                                    if(String.Compare(maxDotNetVersion, name) < 0) maxDotNetVersion = name;
                                } // if
                            } // if
                        } // for
                    } // if
                } // foreach
            } // using
            return maxDotNetVersion;
        }

        protected void log(string message){
            if(printVerification) Console.WriteLine(message);
        }

    } // class
}

Answer 16

您可以获得有用的字符串，而无需接触注册表或引用可能已加载或未加载的程序集。 mscorlib.dll 和其他系统程序集定义了 AssemblyFileVersionAttribute，并且基于 Visual Studio 提供的参考程序集，它对于每个版本的 .NET 似乎都是唯一的。

string version = (typeof(string).Assembly
    .GetCustomAttributes(typeof(AssemblyFileVersionAttribute), false)
    .FirstOrDefault() as AssemblyFileVersionAttribute)?.Version;

4.5 版本有点偏离，因为该版本中标记为 4.0，但 4.6 以后的版本似乎至少有次要版本匹配。 这样做似乎比依赖某些安装程序注册表项并必须与一组固定值进行比较更能适应未来的情况。

我在这里找到了参考程序集：

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework

我在哪里获得了以下版本：

4.0 = 4.0.30319.1
4.5 = 4.0.30319.18020
4.5.1 = 4.0.30319.18402
4.5.2 = 4.0.30319.34211
4.6 = 4.6.81.0
4.6.1 = 4.6.1055.0
4.7.2 = 4.7.3062.0
4.8 = 4.8.3761.0

Answer 17

使用 .NET 4.6.2 进行更新。 检查与之前响应相同的注册表中的 Release 值：

RegistryKey registry_key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full");
if (registry_key == null)
    return false;
var val = registry_key.GetValue("Release", 0);
UInt32 Release = Convert.ToUInt32(val);

if (Release >= 394806) // 4.6.2 installed on all other Windows (different than Windows 10)
                return true;
if (Release >= 394802) // 4.6.2 installed on Windows 10 or later
                return true;

Answer 18

对于那些寻找所有 .net 相关事物版本的人。

我结合了.net core+framework相关信息。

namespace DotNetVersions
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Currently installed \"classic\" .NET Versions in the system:");

            //Show all the installed versions
            Get1To45VersionFromRegistry();
            Get45PlusFromRegistry();


            Process p = new Process();
            p.StartInfo = new ProcessStartInfo()
            {
                FileName = "powershell.exe",
                Arguments = $"dotnet --info",
                UseShellExecute = false,
                CreateNoWindow = true,
                RedirectStandardOutput = true,
            };
            p.Start();
            string output = p.StandardOutput.ReadToEnd();
            p.WaitForExit();
            Console.WriteLine(output);
        }

        //Writes the version
        private static void WriteVersion(string version, string spLevel = "")
        {
            version = version.Trim();
            if (string.IsNullOrEmpty(version))
                return;

            string spLevelString = "";
            if (!string.IsNullOrEmpty(spLevel))
                spLevelString = " Service Pack " + spLevel;

            Console.WriteLine($"{version}{spLevelString}");
        }
        private static void Get1To45VersionFromRegistry()
        {
            // Opens the registry key for the .NET Framework entry.
            using (RegistryKey ndpKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
            {
                foreach (string versionKeyName in ndpKey.GetSubKeyNames())
                {
                    // Skip .NET Framework 4.5 version information.
                    if (versionKeyName == "v4")
                    {
                        continue;
                    }

                    if (versionKeyName.StartsWith("v"))
                    {

                        RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                        // Get the .NET Framework version value.
                        string name = (string)versionKey.GetValue("Version", "");
                        // Get the service pack (SP) number.
                        string sp = versionKey.GetValue("SP", "").ToString();

                        // Get the installation flag, or an empty string if there is none.
                        string install = versionKey.GetValue("Install", "").ToString();
                        if (string.IsNullOrEmpty(install)) // No install info; it must be in a child subkey.
                            WriteVersion(name);
                        else
                        {
                            if (!(string.IsNullOrEmpty(sp)) && install == "1")
                            {
                                WriteVersion(name, sp);
                            }
                        }
                        if (!string.IsNullOrEmpty(name))
                        {
                            continue;
                        }
                        foreach (string subKeyName in versionKey.GetSubKeyNames())
                        {
                            RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                            name = (string)subKey.GetValue("Version", "");
                            if (!string.IsNullOrEmpty(name))
                                sp = subKey.GetValue("SP", "").ToString();

                            install = subKey.GetValue("Install", "").ToString();
                            if (string.IsNullOrEmpty(install)) //No install info; it must be later.
                                WriteVersion(name);
                            else
                            {
                                if (!(string.IsNullOrEmpty(sp)) && install == "1")
                                {
                                    WriteVersion(name, sp);
                                }
                                else if (install == "1")
                                {
                                    WriteVersion(name);
                                }
                            }
                        }
                    }
                }
            }
        }
        private static void Get45PlusFromRegistry()
        {
            const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";

            using (RegistryKey ndpKey = Registry.LocalMachine.OpenSubKey(subkey))
            {
                if (ndpKey == null)
                    return;
                //First check if there's an specific version indicated
                if (ndpKey.GetValue("Version") != null)
                {
                    WriteVersion(ndpKey.GetValue("Version").ToString());
                }
                else
                {
                    if (ndpKey != null && ndpKey.GetValue("Release") != null)
                    {
                        WriteVersion(
                            CheckFor45PlusVersion(
                                    (int)ndpKey.GetValue("Release")
                                )
                        );
                    }
                }
            }

            // Checking the version using >= enables forward compatibility.
            string CheckFor45PlusVersion(int releaseKey)
            {
                if (releaseKey >= 528040)
                    return "4.8";
                if (releaseKey >= 461808)
                    return "4.7.2";
                if (releaseKey >= 461308)
                    return "4.7.1";
                if (releaseKey >= 460798)
                    return "4.7";
                if (releaseKey >= 394802)
                    return "4.6.2";
                if (releaseKey >= 394254)
                    return "4.6.1";
                if (releaseKey >= 393295)
                    return "4.6";
                if (releaseKey >= 379893)
                    return "4.5.2";
                if (releaseKey >= 378675)
                    return "4.5.1";
                if (releaseKey >= 378389)
                    return "4.5";
                // This code should never execute. A non-null release key should mean
                // that 4.5 or later is installed.
                return "";
            }
        }
    }
}

示例输出，

Currently installed "classic" .NET Versions in the system:
2.0.50727.4927 Service Pack 2
3.0.30729.4926 Service Pack 2
3.5.30729.4926 Service Pack 1
4.0.0.0
4.8.03761
.NET SDK (reflecting any global.json):
 Version:   5.0.102
 Commit:    71365b4d42

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.17134
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.102\

Host (useful for support):
  Version: 5.0.2
  Commit:  cb5f173b96

.NET SDKs installed:
  1.1.10 [C:\Program Files\dotnet\sdk]
  2.1.202 [C:\Program Files\dotnet\sdk]
  2.1.402 [C:\Program Files\dotnet\sdk]
  2.1.518 [C:\Program Files\dotnet\sdk]
  3.0.100 [C:\Program Files\dotnet\sdk]
  5.0.102 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 1.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
  https://aka.ms/dotnet-download

Answer 19

有点大，但看起来它是最新的微软奇怪的东西：

    public static class Versions
    {
        static Version 
            _NET;

        static SortedList<String,Version>
            _NETInstalled;

#if NET40
#else
        public static bool VersionTry(String S, out Version V)
        {
            try
            { 
                V=new Version(S); 
                return true;
            }
            catch
            {
                V=null;
                return false;
            }
        }
#endif
        const string _NetFrameWorkKey = "SOFTWARE\\Microsoft\\NET Framework Setup\\NDP";
        static void FillNetInstalled()
        {
            if (_NETInstalled == null)
            {
                _NETInstalled = new SortedList<String, Version>(StringComparer.InvariantCultureIgnoreCase);
                RegistryKey
                    frmks = Registry.LocalMachine.OpenSubKey(_NetFrameWorkKey);
                string[]
                    names = frmks.GetSubKeyNames();
                foreach (string name in names)
                {
                    if (name.StartsWith("v", StringComparison.InvariantCultureIgnoreCase) && name.Length > 1)
                    {
                        string
                            f, vs;
                        Version
                            v;
                        vs = name.Substring(1);
                        if (vs.IndexOf('.') < 0)
                            vs += ".0";
#if NET40
                        if (Version.TryParse(vs, out v))
#else
                        if (VersionTry(vs, out v))
#endif
                        {
                            f = String.Format("{0}.{1}", v.Major, v.Minor);
#if NET40
                            if (Version.TryParse((string)frmks.OpenSubKey(name).GetValue("Version"), out v))
#else
                            if (VersionTry((string)frmks.OpenSubKey(name).GetValue("Version"), out v))
#endif
                            {
                                if (!_NETInstalled.ContainsKey(f) || v.CompareTo(_NETInstalled[f]) > 0)
                                    _NETInstalled[f] = v;
                            }
                            else
                            { // parse variants
                                Version
                                    best = null;
                                if (_NETInstalled.ContainsKey(f))
                                    best = _NETInstalled[f];
                                string[]
                                    varieties = frmks.OpenSubKey(name).GetSubKeyNames();
                                foreach (string variety in varieties)
#if NET40
                                    if (Version.TryParse((string)frmks.OpenSubKey(name + '\\' + variety).GetValue("Version"), out v))
#else
                                    if (VersionTry((string)frmks.OpenSubKey(name + '\\' + variety).GetValue("Version"), out v))
#endif
                                    {
                                        if (best == null || v.CompareTo(best) > 0)
                                        {
                                            _NETInstalled[f] = v;
                                            best = v;
                                        }
                                        vs = f + '.' + variety;
                                        if (!_NETInstalled.ContainsKey(vs) || v.CompareTo(_NETInstalled[vs]) > 0)
                                            _NETInstalled[vs] = v;
                                    }
                            }
                        }
                    }
                }
            }
        } // static void FillNetInstalled()

        public static Version NETInstalled
        {
            get
            {
                FillNetInstalled();
                return _NETInstalled[_NETInstalled.Keys[_NETInstalled.Count-1]];
            }
        } // NETInstalled

        public static Version NET
        {
            get
            {
                FillNetInstalled();
                string
                    clr = String.Format("{0}.{1}", Environment.Version.Major, Environment.Version.Minor);
                Version
                    found = _NETInstalled[_NETInstalled.Keys[_NETInstalled.Count-1]];
                if(_NETInstalled.ContainsKey(clr))
                    return _NETInstalled[clr];

                for (int i = _NETInstalled.Count - 1; i >= 0; i--)
                    if (_NETInstalled.Keys[i].CompareTo(clr) < 0)
                        return found;
                    else
                        found = _NETInstalled[_NETInstalled.Keys[i]];
                return found;
            }
        } // NET
    }

Answer 20

从版本 4.5 开始，Microsoft 更改了在注册表中存储 .NET Framework 指示器的方式。 有关如何检索 .NET 框架和 CLR 版本的官方指南可以在此处找到：https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx

我包含了其代码的修改版本以解决赏金问题关于如何确定 4.5 及更高版本的 .NET 框架的问题：

using System;
using System.Reflection;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Win32;

namespace stackoverflowtesting
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<int, String> mappings = new Dictionary<int, string>();

            mappings[378389] = "4.5";
            mappings[378675] = "4.5.1 on Windows 8.1";
            mappings[378758] = "4.5.1 on Windows 8, Windows 7 SP1, and Vista";
            mappings[379893] = "4.5.2";
            mappings[393295] = "4.6 on Windows 10";
            mappings[393297] = "4.6 on Windows not 10";

            using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\"))
            {
                int releaseKey = Convert.ToInt32(ndpKey.GetValue("Release"));
                if (true)
                {
                    Console.WriteLine("Version: " + mappings[releaseKey]);
                }
            }
            int a = Console.Read();
        }
    }
}

Answer 21

这是我找到的解决方案：

private static string GetDotNetVersion()
{
  var v4 = (string)Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full", false)?.GetValue("Version");
  if(v4 != null)
    return v4;
  var v35 = (string)Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5", false)?.GetValue("Version");
  if(v35 != null)
    return v35;
  var v3 = (string)Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.0", false)?.GetValue("Version");
  return v3 ?? "< 3";
}

Answer 22

        public static class DotNetHelper
{
    public static Version InstalledVersion
    {
        get
        {
            string framework = null;

            try
            {
                using (var ndpKey =
            Registry.LocalMachine.OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\"))
                {
                    if (ndpKey != null)
                    {
                        var releaseKey = ndpKey.GetValue("Release");
                        if (releaseKey != null)
                        {
                            framework = CheckFor45PlusVersion(Convert.ToInt32(releaseKey));
                        }
                        else
                        {
                            string[] versionNames = null;
                            using (var installedVersions =
                                Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP"))
                            {
                                if (installedVersions != null) versionNames = installedVersions.GetSubKeyNames();
                            }


                            try
                            {
                                if (versionNames != null && versionNames.Length > 0)
                                {
                                    framework = versionNames[versionNames.Length - 1].Remove(0, 1);
                                }
                            }
                            catch (FormatException)
                            {

                            }
                        }
                    }
                }
            }
            catch (SecurityException)
            {
            }

            return framework != null ? new Version(framework) : null;
        }
    }

    private static string CheckFor45PlusVersion(int releaseKey)
    {
        if (releaseKey >= 460798)
            return "4.7";
        if (releaseKey >= 394802)
            return "4.6.2";
        if (releaseKey >= 394254)
            return "4.6.1";
        if (releaseKey >= 393295)
            return "4.6";
        if (releaseKey >= 379893)
            return "4.5.2";
        if (releaseKey >= 378675)
            return "4.5.1";
        // This code should never execute. A non-null release key should mean
        // that 4.5 or later is installed.
        return releaseKey >= 378389 ? "4.5" : null;
    }
}

Answer 23

如果您的计算机已连接到互联网，请转至 smallestdotnet，下载并执行 .NET 检查器可能是最简单的方法。

如果您需要确定版本的实际方法，请查看 github 上的源，尤其是。 Constants.cs 这将为您的 .net 4.5 提供帮助然后，修订部分是相关部分：

                           { int.MinValue, "4.5" },
                           { 378389, "4.5" },
                           { 378675, "4.5.1" },
                           { 378758, "4.5.1" },
                           { 379893, "4.5.2" },
                           { 381029, "4.6 Preview" },
                           { 393273, "4.6 RC1" },
                           { 393292, "4.6 RC2" },
                           { 393295, "4.6" },
                           { 393297, "4.6" },
                           { 394254, "4.6.1" },
                           { 394271, "4.6.1" },
                           { 394747, "4.6.2 Preview" },
                           { 394748, "4.6.2 Preview" },
                           { 394757, "4.6.2 Preview" },
                           { 394802, "4.6.2" },
                           { 394806, "4.6.2" },

Answer 24

我发现使用 Version 类更容易：（

using Microsoft.Win32;
using System.Runtime.InteropServices;

namespace System.Runtime.InteropServices {
  public static class RuntimeInformationEx {

    public static Version? GetDotnetFrameworkVersion() {
      using var key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full");
      if (key is object) {
        if (!Int32.TryParse(key.GetValue("Release", "").ToString(), out var release)) return null;
        return release switch
        {
          378389 => new Version(4, 5, 0),
          378675 => new Version(4, 5, 1),
          378758 => new Version(4, 5, 1),
          379893 => new Version(4, 5, 2),
          393295 => new Version(4, 6, 0),
          393297 => new Version(4, 6, 0),
          394254 => new Version(4, 6, 1),
          394271 => new Version(4, 6, 1),
          394802 => new Version(4, 6, 2),
          394806 => new Version(4, 6, 2),
          460798 => new Version(4, 7, 0),
          460805 => new Version(4, 7, 0),
          461308 => new Version(4, 7, 1),
          461310 => new Version(4, 7, 1),
          461808 => new Version(4, 7, 2),
          461814 => new Version(4, 7, 2),
          528040 => new Version(4, 8, 0),
          528209 => new Version(4, 8, 0),
          528049 => new Version(4, 8, 0),
          _ => null
        };

      } else { // .NET version < 4.5
        using var key1 = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP");
        if (key1 is null) return null;
        var parts = key1.GetSubKeyNames()[^1].Substring(1).Split('.'); // get lastsub key, remove 'v' prefix, and split
        if (parts.Length == 2) parts = new string[] { parts[0], parts[1], "0" };
        if (parts.Length != 3) return null;
        Func<string, int> Parse = s => Int32.TryParse(s, out var i) ? i : -1;
        try { return new Version(Parse(parts[0]), Parse(parts[1]), Parse(parts[2])); } catch { return null; }
      }
    }

    public static Version? GetDotnetCoreVersion() {
      if (!RuntimeInformation.FrameworkDescription.StartsWith(".NET Core ")) return null;
      var parts = RuntimeInformation.FrameworkDescription.Substring(10).Split('.');
      if (parts.Length == 2) parts = new string[] { parts[0], parts[1], "0" };
      if (parts.Length != 3) return null;
      Func<string, int> Parse = s => Int32.TryParse(s, out var i) ? i : -1;
      try { return new Version(Parse(parts[0]), Parse(parts[1]), Parse(parts[2])); } catch { return null; }
    }
  }
}

代码是 C#8）