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The WM_NCLBUTTONDOWN message is posted when the user presses the left mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted.
A window receives this message through its WindowProc function.
LRESULT CALLBACK WindowProc( HWND hwnd, // handle to window UINT uMsg, // WM_NCLBUTTONDOWN WPARAM wParam, // hit-test value LPARAM lParam // cursor position );
If an application processes this message, it should return zero.
The DefWindowProc function tests the specified point to find the location of the cursor and performs the appropriate action. If appropriate, DefWindowProc sends the WM_SYSCOMMAND message to the window.
You can also use the GET_X_LPARAM and GET_Y_LPARAM macros to extract the values of the x- and y- coordinates from lParam.
Windows NT/2000 or later: Requires Windows NT 3.1 or later. Windows 95/98/Me: Requires Windows 95 or later. Header: Declared in Winuser.h; include Windows.h.
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Notebook exported on Monday, 7 July 2008, 18:56:50 PM Eastern Daylight Time