DefFrameProc function

Provides default processing for any window messages that the window procedure of a multiple-document interface (MDI) frame window does not process. All window messages that are not explicitly processed by the window procedure must be passed to the DefFrameProc function, not the DefWindowProc function.

Syntax


LRESULT WINAPI DefFrameProc(
  _In_  HWND hWnd,
  _In_  HWND hWndMDIClient,
  _In_  UINT uMsg,
  _In_  WPARAM wParam,
  _In_  LPARAM lParam
);

Parameters

hWnd [in]

Type: HWND

A handle to the MDI frame window.

hWndMDIClient [in]

Type: HWND

A handle to the MDI client window.

uMsg [in]

Type: UINT

The message to be processed.

wParam [in]

Type: WPARAM

Additional message-specific information.

lParam [in]

Type: LPARAM

Additional message-specific information.

Return value

Type:

Type: LRESULT

The return value specifies the result of the message processing and depends on the message. If the hWndMDIClient parameter is NULL, the return value is the same as for the DefWindowProc function.

Remarks

When an application's window procedure does not handle a message, it typically passes the message to the DefWindowProc function to process the message. MDI applications use the DefFrameProc and DefMDIChildProc functions instead of DefWindowProc to provide default message processing. All messages that an application would usually pass to DefWindowProc (such as nonclient messages and the WM_SETTEXT message) should be passed to DefFrameProc instead. The DefFrameProc function also handles the following messages.

MessageResponse
WM_COMMAND Activates the MDI child window that the user chooses. This message is sent when the user chooses an MDI child window from the window menu of the MDI frame window. The window identifier accompanying this message identifies the MDI child window to be activated.
WM_MENUCHAR Opens the window menu of the active MDI child window when the user presses the ALT+ – (minus) key combination.
WM_SETFOCUS Passes the keyboard focus to the MDI client window, which in turn passes it to the active MDI child window.
WM_SIZE Resizes the MDI client window to fit in the new frame window's client area. If the frame window procedure sizes the MDI client window to a different size, it should not pass the message to the DefWindowProc function.

 

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Winuser.h (include Windows.h)

Library

User32.lib

DLL

User32.dll

Unicode and ANSI names

DefFrameProcW (Unicode) and DefFrameProcA (ANSI)

See also

Reference
DefMDIChildProc
DefWindowProc
WM_SETTEXT
Conceptual
Multiple Document Interface

 

 

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