WM_MDIACTIVATE message

An application sends the WM_MDIACTIVATE message to a multiple-document interface (MDI) client window to instruct the client window to activate a different MDI child window.

#define WM_MDIACTIVATE                  0x0222

Parameters

wParam

A handle to the MDI child window to be activated.

lParam

This parameter is not used.

Return value

Type: LRESULT

If an application sends this message to an MDI client window, the return value is zero.

An MDI child window should return zero if it processes this message.

Remarks

As the client window processes this message, it sends WM_MDIACTIVATE to the child window being deactivated and to the child window being activated. The message parameters received by an MDI child window are as follows:

wParam

A handle to the MDI child window being deactivated.

lParam

A handle to the MDI child window being activated.

An MDI child window is activated independently of the MDI frame window. When the frame window becomes active, the child window last activated by using the WM_MDIACTIVATE message receives the WM_NCACTIVATE message to draw an active window frame and title bar; the child window does not receive another WM_MDIACTIVATE message.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Winuser.h (include Windows.h)

See also

Reference

WM_MDIGETACTIVE

WM_MDINEXT

WM_NCACTIVATE

Conceptual

Multiple Document Interface