WM_SHOWWINDOW message
Sent to a window when the window is about to be hidden or shown.
A window receives this message through its WindowProc function.
#define WM_SHOWWINDOW 0x0018
Parameters
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wParam
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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.
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lParam
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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.
Value Meaning - SW_OTHERUNZOOM
- 4
The window is being uncovered because a maximize window was restored or minimized. - SW_OTHERZOOM
- 2
The window is being covered by another window that has been maximized. - SW_PARENTCLOSING
- 1
The window's owner window is being minimized. - SW_PARENTOPENING
- 3
The window's owner window is being restored.
Return value
Type: LRESULT
If an application processes this message, it should return zero.
Remarks
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.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|
See also
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Reference
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Conceptual