public DragBehavior(UIElement DraggableArea, UIElement DraggableElement, UIElement DragContainer)
{
var drag = new { X = 0.0, Y = 0.0 }.ToDefault();
DraggableArea.MouseLeftButtonDown +=
(sender, args) =>
{
if (DragStart != null)
DragStart();
var p = args.GetPosition(DraggableElement);
drag = new { p.X, p.Y };
};
DragContainer.MouseMove +=
(sender, args) =>
{
if (drag == null)
return;
var p = args.GetPosition(DragContainer);
var q = new { X = SnapX(p.X - drag.X), Y = SnapY(p.Y - drag.Y) };
DraggableElement.MoveTo(q.X, q.Y);
};
DragContainer.MouseLeftButtonUp +=
(sender, args) =>
{
if (drag == null)
return;
if (DragStop != null)
DragStop();
drag = null;
};
}