c++ - Post messages to model dialog

Question

I'm planning to create modeless dialog and to receive messages from another thread. According to my understanding to creating modeless dialog I need to create CWinThread and some frame or dialog inside of CWinThread derived class object. But do I really need to create frame/dialog? Why I can't post messages direct to CWinThread derived class object?

Answer 1

You don't need a dialog to receive messages, but you do need a window handle. That window handle does not need to be associated with something visual. What I think you need is a message only window.

In MFC you can do this with CWnd using the CreateEx method to create the message only window. Pass HWND_MESSAGE to the hWndParent parameter of CreateEx.

It is true that you can create a hidden modeless dialog just to receive messages. However, this is grossly wasteful. What's more, MFC is designed around the concept that dialogs are created in the main UI thread. So for a number of different reasons you really do want to avoid creating a dialog just to receive messages in a thread. Use a message only window.