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Q68556: DlgMain.exe Uses a Dialog Box as the Main Window

Article: Q68556
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.0,3.1
Operating System(s): 
Keyword(s): _IK kbfile kbsample kb16bitonly kbDlg kbGrpDSUser kbOSWin310 kbOSWin300
Last Modified: 05-DEC-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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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:

- 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.

MORE INFORMATION
================

The following files are available for download from the Microsoft Download
Center:

DlgMain.exe

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.


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          : _IK kbfile kbsample kb16bitonly kbDlg kbGrpDSUser kbOSWin310 kbOSWin300 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

=============================================================================

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