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WM_NCMOUSEHOVER message

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Posted to a window when the cursor hovers over the nonclient area of the window for the period of time specified in a prior call to TrackMouseEvent.

A window receives this message through its WindowProc function.

#define WM_NCMOUSEHOVER                 0x02A0

Parameters

wParam

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.

lParam

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 value

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

Remarks

Hover tracking stops when this message is generated. The application must call TrackMouseEvent again if it requires further tracking of mouse hover behavior.

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.

xPos = GET_X_LPARAM(lParam); 
yPos = GET_Y_LPARAM(lParam);

Important

Do not use the LOWORD or HIWORD macros to extract the x- and y- coordinates of the cursor position because these macros return incorrect results on systems with multiple monitors. Systems with multiple monitors can have negative x- and y- coordinates, and LOWORD and HIWORD treat the coordinates as unsigned quantities.

Requirements

Requirement Value
Minimum supported client
 Windows 2000 Professional [desktop apps only]
Minimum supported server
 Windows 2000 Server [desktop apps only]
Header
Winuser.h (include Windowsx.h)

See also

Reference

DefWindowProc

GET_X_LPARAM

GET_Y_LPARAM

TrackMouseEvent

TRACKMOUSEEVENT

WM_NCHITTEST

WM_MOUSEHOVER

Conceptual

Mouse Input

Other Resources

MAKEPOINTS

POINTS