我是否必须从 ConfigurationSection 派生才能支持每用户设置？

发布于 2024-07-19 05:28:51 字数 1575 浏览 10 评论 0原文

我正在研究 .NET 的配置支持（ConfigurationManager 类和相关支持类）。我想编写一个应用程序，安装后：

在 foo.exe.config （在程序文件中）中具有默认设置。
用户稍后可以使用应保留的非默认值覆盖设置。
用户的首选项应保留在用户的配置文件中，因为他不应该具有对 Program Files 目录的写入权限。

应用程序应在设置时使用用户的首选项，否则使用默认值。

看起来这应该很简单——这是一种非常常见的模式。但我在这方面的尝试遇到了障碍，我想知道我是否采取了正确的方法。

以下代码产生运行时异常“ConfigurationSection 属性在锁定时无法编辑”。

using System;
using System.Configuration;

namespace DemoAppSettingsProblem
{
    class Program
    {
        static void Main(string[] args)
        {
            Configuration userConfig =
                ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.PerUserRoamingAndLocal);
            if ( userConfig.AppSettings.Settings["foo"] != null )
                userConfig.AppSettings.Settings.Remove("foo");

            userConfig.AppSettings.Settings.Add("foo", "The string is foo.");

            userConfig.Save(ConfigurationSaveMode.Modified);    // exception!
        }
    }
}

问题在于 .NET 定义的部分是使用默认的 allowExeDefinition=MachineToApplication 声明的（请参阅此不错的帖子，作者：微软的 Irena Kennedy）。这会禁止将该部分写入用户的配置文件（本地或漫游）。

因此，我假设我需要使用 allowExeDefinition=MachineToLocalUser 定义自己的部分。但据我从 MSDN 文档得知，这意味着我需要创建自己的配置类，该类派生自 ConfigurationSection。那里的例子表明我要做的工作比我预期的要多，这通常会敲响我的警钟，让我知道我做错了什么。

实现这个目标真的有这么难吗？ .NET 是否提供了一种简单的方法来支持这一点，或者我应该采取完全不同的方法？

原文

I'm playing around with .NET's configuration support (the ConfigurationManager class and related support classes). I would like to write an application that, once installed:

Has default settings in foo.exe.config (in Program Files).
The user may later override the settings with nondefault values which should be persisted.
The user's preferences should be persisted in the user's profile, since he shouldn't have write permissions to the Program Files directory.

The app should use the user's preferences when they're set, otherwise use the defaults.

It seems like this ought to be easy - it's a very common pattern. But my attempts at this are running into bumps and I'm wondering if I'm taking the right approach.

The following code produces the runtime exception "ConfigurationSection properties cannot be edited when locked".

using System;
using System.Configuration;

namespace DemoAppSettingsProblem
{
    class Program
    {
        static void Main(string[] args)
        {
            Configuration userConfig =
                ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.PerUserRoamingAndLocal);
            if ( userConfig.AppSettings.Settings["foo"] != null )
                userConfig.AppSettings.Settings.Remove("foo");

            userConfig.AppSettings.Settings.Add("foo", "The string is foo.");

            userConfig.Save(ConfigurationSaveMode.Modified);    // exception!
        }
    }
}

The problem is that the .NET-defined <appSettings> section is declared with the default allowExeDefinition=MachineToApplication (see this nice post by Microsoft's Irena Kennedy). This prohibits the section from being written to the user's profile (either local or roaming).

So, I assume I need to define my own section, with allowExeDefinition=MachineToLocalUser. But as far as I can tell from the MSDN docs, that means I need to create my own configuration class, derived from ConfigurationSection. The examples there point me toward more work than I was expecting, which usually sets off my alarm bells that I'm doing something wrong.

Is it really this difficult to achieve this? Is there a simple way .NET provides to support this, or should I perhaps be taking a different approach altogether?

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