WM_NCMBUTTONDBLCLK Overview  Group

The WM_NCMBUTTONDBLCLK message is posted when the user double-clicks the middle 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.

WM_NCMBUTTONDBLCLK 

nHittest = (INT) wParam;    // hit-test value 

pts = MAKEPOINTS(lParam);   // position of cursor 

 

Parameters

nHittest

Value of wParam. Specifies the hit-test value returned by the DefWindowProc function as a result of processing the WM_NCHITTEST message. For a list of hit-test values, see WM_NCHITTEST.

pts

Value of lParam. Specifies a POINTS structure that contains the x- and y-coordinates of the cursor. The coordinates are relative to the upper-left corner of the screen.

Return Values

If an application processes this message, it should return zero.

Remarks

A window need not have the CS_DBLCLKS style to receive WM_NCMBUTTONDBLCLK messages.

Windows generates a WM_NCMBUTTONDBLCLK message when the user presses, releases, and again presses the middle mouse button within the system’s double-click time limit. Double-clicking the middle mouse button actually generates four messages: WM_NCMBUTTONDOWN, WM_NCMBUTTONUP, WM_NCMBUTTONDBLCLK, and WM_NCMBUTTONUP again.

An application can use the MAKEPOINTS macro to convert the lParam parameter to a POINTS structure.

If it is appropriate to do so, the system sends the WM_SYSCOMMAND message to the window.

See Also

DefWindowProc, MAKEPOINTS, POINTS, WM_NCHITTEST, WM_NCMBUTTONDOWN, WM_NCMBUTTONUP, WM_SYSCOMMAND