Sent to a window when the window is about to be hidden or shown.
A window receives this message through its WindowProc function.
Indicates whether a window is being shown. If wParam is TRUE, the window is being shown. If wParam is FALSE, the window is being hidden.
The status of the window being shown. If lParam is zero, the message was sent because of a call to the ShowWindow function; otherwise, lParam is one of the following values.
If an application processes this message, it should return zero.
The DefWindowProc function hides or shows the window, as specified by the message. If a window has the WS_VISIBLE style when it is created, the window receives this message after it is created, but before it is displayed. A window also receives this message when its visibility state is changed by the ShowWindow or ShowOwnedPopups function.
The WM_SHOWWINDOW message is not sent under the following circumstances:
- When a top-level, overlapped window is created with the WS_MAXIMIZE or WS_MINIMIZE style.
- When the SW_SHOWNORMAL flag is specified in the call to the ShowWindow function.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|