C# Signature:
[DllImport("user32.dll", SetLastError=true)]
static extern bool TrackMouseEvent(ref TRACKMOUSEEVENT lpEventTrack);
User-Defined Types:
None.
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
// C#
// Sets the hover time to 3sec and resets MouseEnter so the cursor does not have to
// leave the control to hover again
[DllImport("user32.dll")]
static extern int TrackMouseEvent(ref TRACKMOUSEEVENT lpEventTrack);
[StructLayout(LayoutKind.Sequential)]
public struct TRACKMOUSEEVENT
{
public Int32 cbSize; // using Int32 instead of UInt32 is safe here, and this avoids casting the result of Marshal.SizeOf()
[MarshalAs(UnmanagedType.U4)]
public TMEFlags dwFlags;
public IntPtr hWnd;
public UInt32 dwHoverTime;
public TRACKMOUSEEVENT(Int32 dwFlags, IntPtr hWnd, UInt32 dwHoverTime)
{
this.cbSize = Marshal.SizeOf(typeof(TRACKMOUSEEVENT));
this.dwFlags = dwFlags;
this.hWnd = hWnd;
this.dwHoverTime = dwHoverTime;
}
}
protected override void OnMouseHover(EventArgs e)
{
OnMouseEnter(e);
base.OnMouseHover(e);
}
TRACKMOUSEEVENT tme; // Define it on the outside so you dont recreate it each time the mouse enters
protected override void OnMouseEnter(EventArgs e)
{
base.OnMouseEnter(e);
tme = new TRACKMOUSEEVENT();
tme.hWnd = this.Handle;
tme.cbSize = Marshal.SizeOf(typeof(TRACKMOUSEEVENT)); // make sure it gets correct size in different platforms
tme.dwFlags = TMEFlags.TME_HOVER;
tme.dwHoverTime = 1000 * 3;
TrackMouseEvent(ref tme);
}
/// <summary>
/// The services requested. This member can be a combination of the following values.
/// </summary>
/// <seealso cref="http://msdn.microsoft.com/en-us/library/ms645604%28v=vs.85%29.aspx"/>
[Flags]
public enum TMEFlags : uint
{
/// <summary>
/// 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.
/// </summary>
TME_CANCEL = 0x80000000,
/// <summary>
/// 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.
/// </summary>
TME_HOVER = 0x00000001,
/// <summary>
/// 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.
/// </summary>
TME_LEAVE = 0x00000002,
/// <summary>
/// The caller wants hover and leave notification for the nonclient areas. Notification is delivered as WM_NCMOUSEHOVER and WM_NCMOUSELEAVE messages.
/// </summary>
TME_NONCLIENT = 0x00000010,
/// <summary>
/// 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.
/// </summary>
TME_QUERY = 0x40000000,
}
Alternative Managed API:
The Control.MouseEnter, Control.MouseLeave and Control.MouseHover events.
