SAMPLE: Sample Code Using a Dialog Box as the Main Window

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.0 and 3.1

SUMMARY

A modeless dialog box can act as the main window of a Windows-based application. Two advantages of this approach are:

• The main window of the application can be created in the Dialog Editor.
• Focus control is managed by Windows as it is for a dialog box.

Download DLGMAIN.EXE, a self-extracting file, from the Microsoft Software Library (MSL) on the following services:

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        Dial (206) 936-6735 to connect to MSDL
        Download DLGMAIN.EXE (size: 21808 bytes) 
  

• Internet (anonymous FTP)

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        Change to the \SOFTLIB\MSLFILES directory
        Get DLGMAIN.EXE (size: 21808 bytes) 
  

MORE INFORMATION

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;

//  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;