Question

How do you create the deafault Save/Open dialog boxes using pure unmanaged Win32 API ?
Following the guide here, the following code is executed when WM_CREATE message is handled in the message loop of the main window:
Ive included <Commdlg.h> also.

            OPENFILENAMEA ofn;
        char Buffer[300];
        fill(Buffer, Buffer + 300, '\0');
        ofn.lStructSize = sizeof(OPENFILENAMEA);
        ofn.hwndOwner = hWnd;
        ofn.lpstrFile = Buffer;
        ofn.nMaxFile = 300;
        ofn.Flags = OFN_EXPLORER;
        ofn.lpstrFilter = NULL;
        ofn.lpstrCustomFilter = NULL;
        ofn.nFilterIndex = 0;
        ofn.lpstrFileTitle = NULL;
        ofn.lpstrInitialDir = NULL;
        ofn.lpstrTitle = NULL;
        out << GetOpenFileNameA(&ofn) << endl;
        out << Buffer << (int)CommDlgExtendedError();

However, this code gives NO output whatsoever. Help?!

Answer 1

the following code is executed when WM_CREATE message is handled

Look in the Output window and observe the first-chance exception notification for 0xc0000005, an AccessViolation exception. There’s a backstop in the Wow64 emulator that swallows exceptions while WM_CREATE is being dispatched.

The exception is caused by not fully initializing the OPENFILENAMEA structure. Quick fix:

 OPENFILENAMEA ofn = {0};

And favor displaying the dialog before calling ShowWindow() instead of the WM_CREATE message handler.