ManagedToNativeComInteropStubAttribute Class

This attribute enables interop developers who have knowledge about marshaling and the inner workings of interop calls to do the following:

• Take advantage of customized interop stubs at build time instead of run time.

• Debug customized interop stubs.

• Provide marshaling capabilities within a stub that the runtime does not provide.

• Provide user-specific method dispatch capabilities.

You apply the attribute on a method in an interface to specify a corresponding stub method for managed-to-native COM interop.

If this attribute is encountered during run time, the common language runtime does not dynamically generate an interop stub. Instead, it invokes the custom stub that was created at build time.

The ManagedToNativeComInteropStubAttribute attribute has the following characteristics:

• The attribute can be used only on methods from interfaces that are marked [ComImport]. If the attribute is applied to non-interface types, it is ignored by the runtime.

• The attribute can be used only once on the same method in an interface. If it is used more than once, the compiler generates a duplicated attribute error.

• The attribute is not inheritable from a base interface. Derived interfaces must explicitly assign the attribute.

• The assembly that contains the attributed method must also contain the customized stub.

Overloaded stub methods are valid. Although you specify only the type and the name of the stub method, the runtime will discover the corresponding stub. It does this by examining all the arguments on the interface method, and then performing full signature matching by using an explicit this pointer.

It is also possible for multiple methods in an interface to share the same stub method; however, you should be careful when you use shared stubs.

Note
Stub methods must be static.

You could inform the runtime to use a customized interop stub at build time instead of run time with the following C# code:

[ComImport]
interface IMyInterface
{
    [ManagedToNativeComInteropStubAttribute(typeof(TestStubClass),
              "ForwardTestStub")]
    void GetString (string arg);
}

You could then use the following code to declare the corresponding stub method:

class TestStubClass
{
    internal static void ForwardTestStub(IMyInterface thisObject,
             string arg) {…}
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference