Centering a Dialog Box on the Screen

• Microsoft Windows Software Development Kit (SDK) versions 3.1
• Microsoft Win32 Application Programming Interface (API) included with:

      - Microsoft Windows NT versions 3.5 and 3.51
  

When an application developed for the Microsoft Windows graphical environment displays a dialog box, centering the dialog box on the screen is sometimes desirable. However, on systems with high- resolution displays, the application displaying the dialog box may be nowhere near the center of the screen. In these cases, it is preferable to place the dialog near the application requesting input.

To center a dialog box on the screen before it is visible, add the following lines to the processing of the WM_INITDIALOG message:

    {
    RECT rc;

    GetWindowRect(hDlg, &rc);

    SetWindowPos(hDlg, NULL,
       ((GetSystemMetrics(SM_CXSCREEN) - (rc.right - rc.left)) / 2),
       ((GetSystemMetrics(SM_CYSCREEN) - (rc.bottom - rc.top)) / 2),
       0, 0, SWP_NOSIZE | SWP_NOACTIVATE);
    }

Under Windows 95, you should use the new style DS_CENTER to get the same effect.