The WM_PARENTNOTIFY message is sent to the parent of a child window when the child window is created or destroyed, or when the user clicks a mouse button while the cursor is over the child window. When the child window is being created, the system sends WM_PARENTNOTIFY just before the CreateWindow or CreateWindowEx function that creates the window returns. When the child window is being destroyed, the system sends the message before any processing to destroy the window takes place.
A window receives this message through its WindowProc function.
Syntax
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WM_PARENTNOTIFY
WPARAM wParam
LPARAM lParam;
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Parameters
- wParam
-
The low-order word of
wParam specifies the event for which the parent is being notified. This parameter can be one of the following values.
WM_CREATE- The child window is being created.
WM_DESTROY- The child window is being destroyed.
WM_LBUTTONDOWN- The user has placed the cursor over the child window and has clicked the left mouse button.
WM_MBUTTONDOWN- The user has placed the cursor over the child window and has clicked the middle mouse button.
WM_RBUTTONDOWN- The user has placed the cursor over the child window and has clicked the right mouse button.
WM_XBUTTONDOWN- Windows 2000/XP: The user has placed the cursor over the child window and has clicked the first or second X button.
- The following table shows values of the low-order word of wParam and the corresponding meanings of the high-order word of wParam.
LOWORD(wParam)- Meaning of HIWORD(wParam)
WM_CREATE- Identifier of the child window.
WM_DESTROY- Identifier of the child window.
WM_LBUTTONDOWN- Undefined.
WM_MBUTTONDOWN- Undefined.
WM_RBUTTONDOWN- Undefined.
WM_XBUTTONDOWN- Windows 2000/XP: Indicates which button was pressed. This parameter can be one of the following values: XBUTTON1
XBUTTON2
- lParam
-
The following table shows values of the low-order word of wParam and the corresponding meanings of lParam.
WM_CREATE- Handle of the child window.
WM_DESTROY- Handle of the child window.
WM_LBUTTONDOWN- The x-coordinate of the cursor is the low-order word, and the y-coordinate of the cursor is the high-order word.
WM_MBUTTONDOWN- The x-coordinate of the cursor is the low-order word, and the y-coordinate of the cursor is the high-order word.
WM_RBUTTONDOWN- The x-coordinate of the cursor is the low-order word, and the y-coordinate of the cursor is the high-order word.
WM_XBUTTONDOWN- The x-coordinate of the cursor is the low-order word, and the y-coordinate of the cursor is the high-order word.
Return Value
If an application processes this message, it should return zero.
Remarks
This message is also sent to all ancestor windows of the child window, including the top-level window.
All child windows, except those that have the WS_EX_NOPARENTNOTIFY extended window style, send this message to their parent windows. By default, child windows in a dialog box have the WS_EX_NOPARENTNOTIFY style, unless the CreateWindowEx function is called to create the child window without this style.
Notification Requirements
| Minimum DLL Version |
None |
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| Header | Declared in Winuser.h, include Windows.h |
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| Minimum operating systems |
Windows 95, Windows NT 3.1 |
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See Also
Windows Overview, CreateWindow, CreateWindowEx, HIWORD, LOWORD, WM_CREATE, WM_DESTROY, WM_LBUTTONDOWN, WM_MBUTTONDOWN, WM_RBUTTONDOWN, WM_XBUTTONDOWN