TRACKMOUSEEVENT structure (winuser.h)

Used by the TrackMouseEvent function to track when the mouse pointer leaves a window or hovers over a window for a specified amount of time.

Syntax

typedef struct tagTRACKMOUSEEVENT {
  DWORD cbSize;
  DWORD dwFlags;
  HWND  hwndTrack;
  DWORD dwHoverTime;
} TRACKMOUSEEVENT, *LPTRACKMOUSEEVENT;

Members

cbSize

Type: DWORD

The size of the TRACKMOUSEEVENT structure, in bytes.

dwFlags

Type: DWORD

The services requested. This member can be a combination of the following values.

Value	Meaning
TME_CANCEL 0x80000000	The caller wants to cancel a prior tracking request. The caller should also specify the type of tracking that it wants to cancel. For example, to cancel hover tracking, the caller must pass the TME_CANCEL and TME_HOVER flags.
TME_HOVER 0x00000001	The caller wants hover notification. Notification is delivered as a WM_MOUSEHOVER message. If the caller requests hover tracking while hover tracking is already active, the hover timer will be reset. This flag is ignored if the mouse pointer is not over the specified window or area.
TME_LEAVE 0x00000002	The caller wants leave notification. Notification is delivered as a WM_MOUSELEAVE message. If the mouse is not over the specified window or area, a leave notification is generated immediately and no further tracking is performed.
TME_NONCLIENT 0x00000010	The caller wants hover and leave notification for the nonclient areas. Notification is delivered as WM_NCMOUSEHOVER and WM_NCMOUSELEAVE messages.
TME_QUERY 0x40000000	The function fills in the structure instead of treating it as a tracking request. The structure is filled such that had that structure been passed to TrackMouseEvent, it would generate the current tracking. The only anomaly is that the hover time-out returned is always the actual time-out and not HOVER_DEFAULT, if HOVER_DEFAULT was specified during the original TrackMouseEvent request.

hwndTrack

Type: HWND

A handle to the window to track.

dwHoverTime

Type: DWORD

The hover time-out (if TME_HOVER was specified in dwFlags), in milliseconds. Can be HOVER_DEFAULT, which means to use the system default hover time-out.

Remarks

The system default hover time-out is initially the menu drop-down time, which is 400 milliseconds. You can call SystemParametersInfo and use SPI_GETMOUSEHOVERTIME to retrieve the default hover time-out.

The system default hover rectangle is the same as the double-click rectangle. You can call SystemParametersInfo and use SPI_GETMOUSEHOVERWIDTH and SPI_GETMOUSEHOVERHEIGHT to retrieve the size of the rectangle within which the mouse pointer has to stay for TrackMouseEvent to generate a WM_MOUSEHOVER message.

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 Windows.h)

See also

Mouse Input