Creating a Hidden MDI Child Window

 Last reviewed: November 2, 1995
Article ID: Q70080
The information in this article applies to:
  • Microsoft Windows Software Development Kit (SDK) versions 3.0 and 3.1
  • Microsoft Win32 Application Programming Interface (API) included with: 

        - Microsoft Windows NT versions 3.5 and 3.51
    - Microsoft Windows 95 version 4.0

SUMMARY

Whenever Windows creates a new multiple-document interface (MDI) child window in response to a WM_MDICREATE message, it makes that child window visible.

The information below describes how to create a hidden MDI child window without causing an unattractive "flash" on the screen as the window is created visible and then hidden.

MORE INFORMATION

A code fragment such as the following can be used to create an invisible MDI child: 

MDICREATESTRUCT mcs;            // structure to pass with WM_MDICREATE
HWND            hWndMDIClient;  // the MDI client window
HWND            hwnd;           // temporary window handle

      ...

// assume that we have already filled out the MDICREATESTRUCT...

// turn off redrawing in the MDI client window
SendMessage(hwndMDIClient, WM_SETREDRAW, FALSE, 0L); 

/*
 * Create the MDI child. It will be created visible, but will not
 * be seen because redrawing to the MDI client has been disabled
*/
hwnd = (WORD)SendMessage(hwndMDIClient, 
                         WM_MDICREATE,
                         0,
                         (LONG)(LPMDICREATESTRUCT)&mcs);

// hide the child
ShowWindow(hwnd, SW_HIDE); 

// turn redrawing in the MDI client back on,
// and force an immediate update
SendMessage(hwndMDIClient, WM_SETREDRAW, TRUE, 0L); InvalidateRect( hwndMDIClient, NULL, TRUE ); UpdateWindow( hwndMDIClient ); 
      ...

Additional reference words: 3.00 3.10 3.50 3.51 4.00 95
KBCategory: kbui
KBSubcategory: UsrMdi

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Last reviewed: November 2, 1995
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.