How to implement COM callbacks in managed C++?

[Guest]

I call from managed C++ a DCOM server interface method that takes a callback
interface as parameter. I cannot figure out how to implement such a callback
object in managed C++. The callback interface (e.gr. ICallback) is defined by
the server type library.

I have figured out that the following code seems to implement a COM object
in managed C++ but how do I implement the callback interface ICallback:

#import "dcom_server.exe" // Import server type library
using namespace System::Runtime::InteropServices;

[GuidAttribute("..."), ClassInterface(ClassInterfaceType::AutoDual)]
public __gc class CallbackImplementation
{
};

I cannot inherit from the ICallback interface because it's unmanaged code.

Any ideas?

Anders

 

[Jochen Kalmbach [MVP]]

Hi anders!

I call from managed C++ a DCOM server interface method that takes a callback
interface as parameter. I cannot figure out how to implement such a callback
object in managed C++. The callback interface (e.gr. ICallback) is defined by
the server type library.

If your server uses late-bindung you can implement the callback like:

<code>
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.AutoDispatch)]
public class MyCallback
{
[DispId(1)]
public void OnXxx(int eventHandle, object data, int result)
{
}
}
</code>

Currently I do not know how to do it if you must provide a early-binding...

--
Greetings
Jochen

My blog about Win32 and .NET
http://blog.kalmbachnet.de/