CDialog has NULL HWND after CDialog::Create()

Question

processingDlg.Create(IDD_PROCESSING);  


HWND hwnd{ processingDlg.GetSafeHwnd() };  

Sadly the returned HWND is null :(

What can I do to get the HWND assigned without actually displaying the dialog?

Answer 1

You're correct Create returned 0 .
What might cause CDialog::Create to return 0?

Create a debug build of your application and use the debugger to step through the call to CDialog::Create. You should be able to do this because the MFC source code is installed as part of a Visual Studio installation that includes installing MFC.

And here's some bonus reading for you to do - Why can't I create my dialog with DialogBox, DialogBoxParam, CreateDialog, CreateDialogParam, or the indirect versions of same?

Answer 2

You're correct Create returned 0 .

This is not quite your normal MFC application.

I have my own main() which does:

   if (!AfxWinInit(::GetModuleHandle(nullptr), nullptr, ::GetCommandLine(), 0))  
   {  
   ZTRACE_RUNTIME("Fatal Error: MFC initialization failed");  
   return 1;  
   }  
   // initialize all the windows stuff we need for now  
   theApp.InitInstance();  

theApp.InitInstance in turn calls CWinApp::InitInstance() and that DOES return 1.

What might cause CDialog::Create to return 0?

Answer 3

Problem solved - the message pump wasn't running at that point - I moved the call to processingDlg.Create() to a mf that was g'teed to be called after the message pump was started.

It was in a ctor that was invoked before the message pump was started.

Thanks
D.

Answer 4

Hmmm In that case I'm baffled (but happy it now works).