HOWTO: How to Create a Minimized/Maximized MDI Child Window

MORE INFORMATION

If you're using a version of Visual C++ earlier than 4.0, it is necessary to derive a class from CMDIChildWnd and substitute the new class name in the CMultiDocTemplate used in your CWinApp-derived InitInstance() function. To do so, use ClassWizard to add a class called CChildFrame derived from CMDIChildWnd. Include the header file in your application's .cpp file. Then change the line indicated below in your InitInstance() function:

    CMultiDocTemplate* pDocTemplate;
    pDocTemplate = new CMultiDocTemplate(
        IDR_MDIAPPTYPE,
        RUNTIME_CLASS(CMDIAppDoc),
        RUNTIME_CLASS(CChildFrame), // change CMDIChildWnd to CChildFrame
        RUNTIME_CLASS(CMDIAppView));
    AddDocTemplate(pDocTemplate);
				

In Visual C++ 4.0, deriving a class from CMDIChildWnd is not required because one is already provided for you.

In the CChildFrame class, override the ActivateFrame() member function as follows:

void CChildFrame::ActivateFrame(int nCmdShow)
{
    if (nCmdShow == -1)
        nCmdShow = SW_SHOWMAXIMIZED;

    CMDIChildWnd::ActivateFrame(nCmdShow);
}