CreateMDIWindow

The CreateMDIWindow function creates a multiple document interface (MDI) child window.

HWND CreateMDIWindow(
  LPTSTR lpClassName,  // pointer to registered child class name
  LPTSTR lpWindowName, // pointer to window name
  DWORD dwStyle,       // window style
  int X,               // horizontal position of window
  int Y,               // vertical position of window
  int nWidth,          // width of window
  int nHeight,         // height of window
  HWND hWndParent,     // handle to parent window (MDI client)
  HINSTANCE hInstance, // handle to application instance
  LPARAM lParam        // application-defined value
);
 

Parameters

lpClassName

Pointer to a null-terminated string specifying the window class of the MDI child window. The class name must have been registered by a call to the RegisterClassEx function.

lpWindowName

Pointer to a null-terminated string that represents the window name. The system displays the name in the title bar of the child window.

dwStyle

Specifies the style of the MDI child window. If the MDI client window is created with the MDIS_ALLCHILDSTYLES window style, this parameter can be any combination of the window styles listed in the description of the CreateWindow function. Otherwise, this parameter can be one or more of the following values:

Value	Meaning
WS_MINIMIZE	Creates an MDI child window that is initially minimized.
WS_MAXIMIZE	Creates an MDI child window that is initially maximized.
WS_HSCROLL	Creates an MDI child window that has a horizontal scroll bar.
WS_VSCROLL	Creates an MDI child window that has a vertical scroll bar.

X

Specifies the initial horizontal position, in client coordinates, of the MDI child window. If this parameter is CW_USEDEFAULT, the MDI child window is assigned the default horizontal position.

Y

Specifies the initial vertical position, in client coordinates, of the MDI child window. If this parameter is CW_USEDEFAULT, the MDI child window is assigned the default vertical position.

nWidth

Specifies the initial width, in device units, of the MDI child window. If this parameter is CW_USEDEFAULT, the MDI child window is assigned the default width.

nHeight

Specifies the initial height, in device units, of the MDI child window. If this parameter is set to CW_USEDEFAULT, the MDI child window is assigned the default height.

hWndParent

Handle to the MDI client window that will be the parent of the new MDI child window.

hInstance

Handle to the instance of the application creating the MDI child window.

lParam

Specifies an application-defined value.

Return Values

If the function succeeds, the return value is the handle to the created window.

If the function fails, the return value is NULL. To get extended error information, call GetLastError.

Remarks

Using the CreateMDIWindow function is similar to sending the WM_MDICREATE message to an MDI client window, except that the function can create an MDI child window in a different thread, while the message cannot.

Windows 95: The system can support a maximum of 16,364 window handles.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in winuser.h.
  Import Library: Use user32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT.

See Also

Multiple Document Interface Overview, Multiple Document Interface Functions, CreateWindow, RegisterClassEx, WM_MDICREATE