使用.NET 4.5和混合程序集时出现未知异常

Question

I have a problem when the new .Net Framework (version 4.5) is installed. I am working on a plugin assembly that is accessed through native code. The library is build using Visual Studio 2010 and with .NET 4.0 as target plattform.

The following code snippet throws an exception in .NET 4.5 and is working fine in .NET 4.0. Any idea how to fix this issue?

#pragma managed(push, off)
#pragma managed(push, on)

static bool ManagedTestFunction() {
    return false;
}

#pragma managed(pop)

static void CheckIfManagedUnmanagedTransitionIsPossible() 
{
    try 
    {
        ManagedTestFunction();
    }
    catch (...) 
    {
        throw misc::mwException(0, _T("The program is not working if .NET Framework 4.5 is installed. Please revert to previous version .NET 4.0!"));
    }
};

Best regards

Michael

Answer 1

我将看看最初引发了什么异常-应该为您提供一个线索，说明为什么代码无法在.NET Framework 4.5下工作。

Answer 2

finally I solve the problem myself. It is maybe a conceptional problem due to some optimization in .NET 4.5. Concider the following example:

// managed class
ref class A
{
}

// native class holding a reference to A
class B 
{
    msclr::gcroot<A^> m_refA;
};

When first crossing the native-managed boundary, the new .NET Framework tries to resolve all managed types that are reference in native classes independent whether they are actually used or not. At that time, it is not yet possible to subscribe to the AppDomain.ResolveAssembly event. If the framework cannot resolve a type, the crash happens.

A possible solution is modify class B such that it stores a reference to a System::Object^ instead and to cast dynamically using "cli_safe((System::Object^) m_refA)"

Best regards

Michael