TrackMouseEvent function

Posts messages when the mouse pointer leaves a window or hovers over a window for a specified amount of time.

Note  The _TrackMouseEvent function calls TrackMouseEvent if it exists, otherwise _TrackMouseEvent emulates TrackMouseEvent.
 

Syntax

BOOL TrackMouseEvent(
  LPTRACKMOUSEEVENT lpEventTrack
);

Parameters

lpEventTrack

Type: LPTRACKMOUSEEVENT

A pointer to a TRACKMOUSEEVENT structure that contains tracking information.

Return Value

Type: BOOL

If the function succeeds, the return value is nonzero .

If the function fails, return value is zero. To get extended error information, call GetLastError.

Remarks

The mouse pointer is considered to be hovering when it stays within a specified rectangle for a specified period of time. Call SystemParametersInfo. and use the values SPI_GETMOUSEHOVERWIDTH, SPI_GETMOUSEHOVERHEIGHT, and SPI_GETMOUSEHOVERTIME to retrieve the size of the rectangle and the time.

The function can post the following messages.

Message Description
WM_NCMOUSEHOVER The same meaning as WM_MOUSEHOVER except this is for the nonclient area of the window.
WM_NCMOUSELEAVE The same meaning as WM_MOUSELEAVE except this is for the nonclient area of the window.
WM_MOUSEHOVER The mouse hovered over the client area of the window for the period of time specified in a prior call to TrackMouseEvent. Hover tracking stops when this message is generated. The application must call TrackMouseEvent again if it requires further tracking of mouse hover behavior.
WM_MOUSELEAVE The mouse left the client area of the window specified in a prior call to TrackMouseEvent. All tracking requested by TrackMouseEvent is canceled when this message is generated. The application must call TrackMouseEvent when the mouse reenters its window if it requires further tracking of mouse hover behavior.

Requirements

   
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header winuser.h (include Windows.h)
Library User32.lib
DLL User32.dll

See Also

Conceptual

Mouse Input

Other Resources

Reference

SystemParametersInfo

TRACKMOUSEEVENT

_TrackMouseEvent