private void GetDragState(ref bool isDragTarget, ref Point dragLocation, DragEventArgs args)
{
ElementDesignerData data = args.Data as ElementDesignerData;
if (data != null)
{
object element =
_grid
[
ClientToGrid(PointToClient(new Point(args.X, args.Y)))
];
if (element == null)
{
dragLocation = ClientToGrid(PointToClient(new Point(args.X, args.Y)));
isDragTarget = true;
}
}
}
protected override void OnDragDrop(DragEventArgs args)
{
base.OnDragDrop(args);
SetDragState(false, Point.Empty);
bool isDragTarget = false;
Point dragLocation = Point.Empty;
GetDragState(ref isDragTarget, ref dragLocation, args);
if (isDragTarget)
{
ElementDesignerData data = args.Data as ElementDesignerData;
if (data != null)
{
_grid[_grid.GetPosition(data.Element)] = null;
_grid[dragLocation] = data.Element;
UpdateRange();
UpdateDesigners(true);
UpdateScrollBars();
PerformLayout();
}
}
}