WM_NCLBUTTONDBLCLK
The
WM_NCLBUTTONDBLCLK message is posted when the user double-clicks 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.
WM_NCLBUTTONDBLCLK
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.
Default Action
The DefWindowProc
function tests the given point to find out the location of the cursor and
performs the appropriate action. If appropriate, DefWindowProc sends the
WM_SYSCOMMAND message
to the window.
Remarks
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:
WM_NCLBUTTONDOWN, WM_NCLBUTTONUP, WM_NCLBUTTONDBLCLK, and WM_NCLBUTTONUP again.
An
application can use the MAKEPOINTS macro to convert the lParam
parameter to a POINTS structure.
See Also