/// <summary>
/// Handles that the dragged pointing device is over in the target UI element.
/// For reference the DragOver event is raised periodically.
/// </summary>
/// <param name="currentPosition">The current pointing device position relative to the target UI element.</param>
/// <param name="hoverEventMode">A HoverEventMode.</param>
/// <param name="hoverTime">A HoverTime.</param>
/// <param name="hoverWidth">A HoverWidth.</param>
/// <param name="hoverHeight">A HoverHeight.</param>
/// <param name="setIsHover">An action that sets a IsHover.</param>
/// <param name="hoverCallback">A callback action that is called when Hover is detected.</param>
public void ProcessOver(Point currentPosition, HoverEventMode hoverEventMode, TimeSpan hoverTime, double hoverWidth, double hoverHeight,
Action <bool> setIsHover, Action <Point, long, Point, long> hoverCallback)
{
if (setIsHover == null)
{
throw new ArgumentNullException("setIsHover");
}
if (hoverCallback == null)
{
throw new ArgumentNullException("hoverCallback");
}
// Gets the point in screen coordinates.
Point currentPositionInScreen = PointToScreen(currentPosition);
// Checks whether the current position is in the hover rectangle...
Vector allowedMoveDistance = new Vector(hoverWidth, hoverHeight);
if (BasePositionInScreen == null || !IsHover(allowedMoveDistance, BasePositionInScreen.Value, currentPositionInScreen))
{
// Resets the base position related values.
BasePositionInScreen = currentPositionInScreen;
BaseTicks = DateTime.Now.Ticks;
_isRaisedAtBasePosition = false;
// Sets that it is not hover.
setIsHover(false);
return;
}
// If the hover event mode is once and the hover event is already raised in the target UI element.
if (hoverEventMode == HoverEventMode.Once && IsRaisedAfterEnter)
{
return;
}
// If the hover event mode is normal and the hover event is already raised at the BasePosition
if (hoverEventMode == HoverEventMode.Normal && _isRaisedAtBasePosition)
{
return;
}
// Checks whether the elapsed ticks are greater than the hover time.
long currentTicks = DateTime.Now.Ticks;
if (!IsHover(hoverTime.Ticks, BaseTicks, currentTicks))
{
return;
}
// Sets that it is hover.
setIsHover(true);
// Calls the hover callback.
CallHoverCallback(hoverCallback, currentPositionInScreen, currentTicks);
// Sets the raised flag.
IsRaisedAfterEnter = true;
_isRaisedAtBasePosition = true;
// Resets the base ticks.
BaseTicks = DateTime.Now.Ticks;
}
/// <summary>
/// Sets a value that describes how hover event is raised.
/// </summary>
/// <param name="obj">The target element.</param>
/// <param name="value">A value that describes how hover event is raised.</param>
/// <seealso cref="HoverEventMode"/>
public static void SetHoverEventMode(DependencyObject obj, HoverEventMode value)
{
obj.SetValue(HoverEventModeProperty, value);
}
