SAMPLE: DlgMain.exe Uses a Dialog Box as the Main Window

ID: Q68556

The information in this article applies to:

SUMMARY

DlgMain.exe is a sample file that demonstrates how to create a modeless dialog box that can act as the main window of a Windows-based application. Two advantages of this approach are:

MORE INFORMATION

The following file is available for download from the Microsoft Software Library: 

 ~ DlgMain.exe (size: 21808 bytes)
For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base: 

   ARTICLE-ID: Q119591
   TITLE     : How to Obtain Microsoft Support Files from
               Online Services
The information below outlines the necessary modifications to the code in GENERIC, a sample application provided with the Windows Software Development Kit (SDK) version 3.0, that will result in a Windows-based application that uses a modeless dialog box as its main window.

To GENERIC.C, make the following changes: 

   //  1. Create a global variable to hold the window handle of the
   //     dialog box.

      HWND hDlgMain;

   //  2. In the WinMain() procedure, declare a FARPROC variable. This
   //     variable holds the procedure-instance address for the dialog
   //     procedure.

      FARPROC lpfn;

   //  3. Modify the CreateWindow() call in InitInstance() to specify 0
   //     (zero) for nWidth and nHeight when the main window is created.
   //     Do this so that the main window is not shown until the size of
   //     the dialog box is known.

      hWnd = CreateWindow("GenericWClass", "Dialog as Main Window",
                WS_OVERLAPPED | WS_CAPTION | WS_MINIMIZEBOX | WS_SYSMENU,
                CW_USEDEFAULT, 0, 0, 0, NULL, NULL, hInstance, NULL);

   //  4. In WinMain(), create a procedure-instance for the dialog
   //     procedure.

      lpfn = MakeProcInstance(Dialog1, hInst);

   //  5. In WinMain, create the dialog box using CreateDialog().

      hDlgMain = CreateDialog(hInst, "DIA1", hWnd, lpfn);

   //  6. Add code to WinMain() to show the dialog box.

      ShowWindow(hDlgMain, SW_SHOW);

   //  7. Windows sends messages to the modeless dialog box through the
   //     program's main message queue. To process messages intended for
   //     the dialog box, modify message queue processing in WinMain() as
   //     follows:

      while (GetMessage(&msg,   // Message structure
                        NULL,   // Handle of window receiving message
                        NULL,   // Lowest message to handle
                        NULL))  // Highest message to handle
      {
         if (hDlgMain == NULL || !IsDialogMessage(hDlgMain, &msg))
         {
         TranslateMessage(&msg); // Translate virtual key codes
         DispatchMessage(&msg);  // Dispatches message to window
         }
      }
      return msg.wParam;     /* Returns the value from PostQuitMessage */ 

   //  8. When the application receives a WM_SETFOCUS message, it must
   //     set the input focus to the control that acts as the
   //     application's main window. Adding the following code to
   //     MainWndProc() processes the WM_SETFOCUS message as required:

      case WM_SETFOCUS:
         SetFocus(hDlgMain);
         break;
In the dialog function, make the remaining changes: 

   //  9. In the dialog function, declare a variable of type RECT to
   //     store the bounding rectangle of the modeless dialog box.

      RECT rect;

   // 10. Retrieve the dimensions of the dialog box. This information
   //     will be used to calculate the size of the parent window.

      case WM_INITDIALOG:
         GetWindowRect(hDlg, &rect);

   // 11. Size the parent window to be the same size as the dialog box.

      SetWindowPos(GetParent(hDlg), // Get the window handle of the
                                    // parent of the dialog box.

        NULL,                       // Identifies a window that in the
                                    // window-manager's list will
                                    // precede the positioned window.
                                    // This is not used for this example.

        0,                          // Specify the x-coordinate of the
                                    // window's upper-left corner.

        0,                          // Specify the x-coordinate of the
                                    // window's upper-left corner.

        rect.right - rect.left,     // Based on the values returned by
                                    // GetWindowRect, calculate the new
                                    // width of the main window.

        rect.bottom - rect.top + GetSystemMetrics(SM_CYCAPTION)
                               + GetSystemMetrics(SM_CYMENU),
                                    // Based on the values returned by
                                    // GetWindowRect, the height of the
                                    // caption bar, and the height of
                                    // the menu bar, calculate the new
                                    // height of the main window.

        SWP_NOMOVE | SWP_NOZORDER);
                                    // Retain current position and
                                    // ordering.

   // 12. When the application receives a WM_CLOSE message, close the
   //     modeless dialog box and post a WM_CLOSE message to the main
   //     window.

      case WM_CLOSE:
         DestroyWindow(hDlg);  // Close the modeless dialog box using
                               // DestroyWindow.
         hDlgMain = NULL;      // Set the handle of the modeless dialog
                               // box to null.
         PostMessage(GetParent(hDlg), WM_CLOSE, NULL, NULL);
         break;
Make one change to GENERIC.RC: Modify the dialog box template to specify the additional style WS_CHILD. Doing so will ensure that the dialog box moves with the parent window as the parent is moved.

Additional query words: Keywords : kbcode kbfile kbsample kb16bitonly kbDlg kbGrpUser kbWinOS310 kbWinOS300

Last Reviewed: December 26, 1998