WM_NCLBUTTONDBLCLK

nHittest = (INT) wParam; /* hit-test code */

pts = MAKEPOINTS(lParam); /* mouse-cursor coordinates */

The WM_NCLBUTTONDBLCLK message is posted when the user double-clicks the left mouse button while the mouse cursor is within the nonclient area of a window. This message is posted to the window that contains the mouse cursor. If a window has the mouse captured, this message is not posted.

Parameters

nHittest

Value of wParam. Specifies the hit-test code returned by the DefWindowProc function as a result of processing the WM_NCHITTEST message. For more information, see the description of the WM_NCHITTEST message.

pts

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

typedef struct tagPOINTS { /* pts */

SHORT x;

SHORT y;

} POINTS;

Return Value

An application should return zero if it processes this message.

Comments

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

Windows generates a WM_NCLBUTTONDBLCLK message when the user presses, releases, and again presses the left mouse button within the system's double-click time limit. Double-clicking the left mouse button actually generates four messages: a WM_NCLBUTTONDOWN message, a WM_NCLBUTTONUP message, the WM_NCLBUTTONDBLCLK message, and another WM_NCLBUTTONUP message.

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

If appropriate, WM_SYSCOMMAND messages are sent.