无法捕获通过 PInvoke 调用的 C dll 引起的异常

发布于 2024-10-17 08:55:11 字数 861 浏览 2 评论 0原文

我正在编写一个 C# .NET 3.5 程序，它使用最新的 MediaInfoLib Dll。
看来它会导致某些文件出现异常。

我想捕获这些异常并确保我的程序继续运行，
但由于某种原因，我无法用简单的 try/catch 语句捕获它。

PInvoke 方法：

    [DllImport("MediaInfo.dll")]
    private static extern IntPtr MediaInfo_New();
    [DllImport("MediaInfo.dll")]
    private static extern IntPtr MediaInfo_Open(IntPtr Handle,MarshalAs(UnmanagedType.LPWStr)] string FileName);

用法：

    Handle = MediaInfo_New();
    try{
        MediaInfo_Open(Handle, FileName)
    } catch { }

调用 MediaInfo_Open(Handle, FileName) 可能会导致异常。
我的程序没有使用 try/catch 语句捕获错误，而是退出并且“vshost32-clr2.exe”崩溃。（它也会在发布版本时崩溃并且没有附加调试器）
在网上搜索后，我发现有人建议选中“启用非托管代码调试”，这只会导致我的程序退出而不会导致 vshost32-clr2.exe 崩溃。

知道我如何捕获异常吗？

原文

I'm writing a C# .NET 3.5 program wich uses the latest MediaInfoLib Dll.
It seems that it causes an exception for some files.

I want to catch those exceptions and ensure my program continues running,
but for some reason I can't catch it with a simple try/catch statement.

PInvoke Methods:

    [DllImport("MediaInfo.dll")]
    private static extern IntPtr MediaInfo_New();
    [DllImport("MediaInfo.dll")]
    private static extern IntPtr MediaInfo_Open(IntPtr Handle,MarshalAs(UnmanagedType.LPWStr)] string FileName);

Usage:

    Handle = MediaInfo_New();
    try{
        MediaInfo_Open(Handle, FileName)
    } catch { }

Calling MediaInfo_Open(Handle, FileName) might cause an exception.
Instead of catching the error with the try/catch statement, my program exits and "vshost32-clr2.exe" crashes. (It also crashes as a release build and with no debugger attached)
After searching the web, I found someone who suggested to check "Enable unmanaged code debugging", which only resulted in my program exiting without vshost32-clr2.exe crashing.

Any idea how I can catch the exception?

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攀登最高峰 2024-10-24 08:55:11

如果非托管 DLL 导致崩溃（而不仅仅是返回某种错误代码），则无法捕获它。一旦脱离了 .NET 运行时的控制，它就完全取决于非托管代码； .NET 运行时无能为力。

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魔 2024-10-24 08:55:11

我也遇到过类似的问题（特别是 BSTR），但希望这会有所帮助。

当从非托管代码内部编组回字符串时，.NET 中存在一个错误（在 4.0 中已修复）。更多解决

方法是更改 P/Invoke 签名以使用 IntPtr 并自行进行字符串编组。

[DllImport("MediaInfo.dll", EntryPoint = "MediaInfo_Open")]
private static extern IntPtr _MediaInfo_Open(IntPtr handle, IntPtr filename);

internal static extern IntPtr MediaInfo_Open(IntPtr handle, string filename)
{
     IntPtr stringPtr = Marshal.StringToBSTR(filename);
     return _MediaInfo_Open(handle, stringPtr);
}

I've had a similar problem (with BSTR specifically) but hopefully this will help.

There is a bug in .NET (fixed in 4.0) when internally marshalling strings back from unmanaged code. More Info

The work-around is to change your P/Invoke signature to use an IntPtr and do the string marshalling yourself.

[DllImport("MediaInfo.dll", EntryPoint = "MediaInfo_Open")]
private static extern IntPtr _MediaInfo_Open(IntPtr handle, IntPtr filename);

internal static extern IntPtr MediaInfo_Open(IntPtr handle, string filename)
{
     IntPtr stringPtr = Marshal.StringToBSTR(filename);
     return _MediaInfo_Open(handle, stringPtr);
}

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