/// <summary>
/// Removes the <see cref="DragAdorner"/>.
/// </summary>
private void RemoveDragAdorner()
{
if (_dragAdorner != null)
{
var adornerLayer = AdornerLayer.GetAdornerLayer(_dragAdorner.AdornedElement);
adornerLayer?.Remove(_dragAdorner);
_dragAdorner = null;
}
}
// Creates or updates the DragAdorner.
private void UpdateDragAdorner(Point mousePosition)
{
// Create new adorner if necessary.
if (_dragAdorner == null && _dropCommandParameter.Data != null)
{
_dragAdorner = new DragAdorner(AssociatedObject)
{
Data = _dropCommandParameter.Data,
DataTemplate = DragTemplate,
};
var adornerLayer = AdornerLayer.GetAdornerLayer(AssociatedObject);
adornerLayer?.Add(_dragAdorner);
}
// Update the position of the adorner.
UpdateDragAdornerPosition(mousePosition);
// Update data.
// (The drop commands can change it to alter the visualization while dropping.)
if (_dragAdorner != null)
_dragAdorner.Data = _dropCommandParameter.Data;
}
