Can I send / receive window messages without a window?

Question

I'm writing a .NET wrapper around an old MFC-based library we have. It's based around a class that sends notifications using window messages; it has a function that lets the user pass in a handle to a window, and that window will receive the messages.

I could just require the users of my wrapper to subclass Control and pass their control's handle in order to receive messages, but that's horrible. I want my wrapper class to have events which fire whenever the old library sends a message, and then I can do the decoding of the message into something sensible. But, I don't want my wrapper class to have to be a control.

Is there a way for me to create a 'dummy' window handle, and receive the messages sent to that handle, without creating a window?

Answer 1

There is a concept of MessageOnly Windows which can help you. You may create an internal message only window in your wrapper class and pass this handle to the old library.

Answer 2

You could try creating a thread with a message pump and sending your messages to that. The thread then raises any necessary events that you want to handle in your C# code.

Answer 3

You can't create a window handle without having a window, since the window handle is the window as far Windows is concerned, but you can make a window without the WS_VISIBLE flag set, and use it for message relaying only. I use that technique sometimes to do cross-thread communication in MFC-only applications (don't tell anyone ;) ). You could derive a (c++) class from CWnd, let it process the messages, and call functions or emit signals for every message that is received. I guess that would make it work with your C# code although I don't have experience with that.