void StartDrag(ListBox parent, Point mousePosition)
{
var vm = this.DataContext as SalesViewModel;
if (vm == null || !String.IsNullOrWhiteSpace(vm.SearchBarItemText))
{
return;
}
UIElement dataContainer;
//get the object source for the selected item
object data = GetObjectDataFromPoint(parent, mousePosition, out dataContainer);
//if the data is not null then start the drag drop operation
if (data != null)
{
RemoveAdorner();//clear the adorner layer from previous adorners
//create a new adorner for the item and add it to the Adorner Layer
adorner = new AdornerDragDrop(containerGrid, dataContainer);
AdornerLayer.GetAdornerLayer(containerGrid).Add(adorner);
//do the drag drop operation and pass the data
DragDrop.DoDragDrop(parent, data, DragDropEffects.Move);
}
}
private void ListBox_DropHandler(object sender, DragEventArgs e)
{
RemoveAdorner();
adorner = null;
var data = e.Data.GetData(typeof(GoodsModel)) as GoodsModel;
if (data == null)
{
return;
}
var destination = (e.OriginalSource as FrameworkElement);
if (destination == null || destination.Tag == null)
{
return;
}
var vm = this.DataContext as SalesViewModel;
if (vm == null)
{
return;
}
vm.ChangeBarItemPosition(data, destination.Tag.ToString());
}
//remove the adorner from the layer
private void RemoveAdorner()
{
if (adorner != null)
{
//remove the adorner
AdornerLayer.GetAdornerLayer(containerGrid).Remove(adorner);
adorner = null;
}
}
protected override void OnPreviewMouseLeftButtonDown(MouseButtonEventArgs e)
{
base.OnPreviewMouseLeftButtonDown(e);
if (e.OriginalSource.GetType() == typeof(RouteItem))
{
Point position = e.GetPosition(this);
// To prevent Mouse "hang" error, release Adorner object if one constructed
if (_adorner != null)
{
AdornerLayer.GetAdornerLayer(_adorner.AdornedElement).Remove(_adorner);
}
// Initialize new Adorner object
_adorner = new AdornerDragDrop(e.OriginalSource as UIElement)
{
StartPoint = position
};
e.Handled = true;
}
}
private void DragFinished(bool cancel)
{
//Release Mouse
Mouse.Capture(null);
// Remove adorner object from rendering layer
AdornerLayer.GetAdornerLayer(_adorner.AdornedElement).Remove(_adorner);
if (_adorner.IsDragStarted && cancel == false)
{
//Move object to new position
if (_adorner.OriginalSource is RouteItem rt)
{
rt.SetBindingPoint(new Point(
_adorner.StartPoint.X + _adorner.LeftOffset - _adorner.ActualWidth / 2,
_adorner.StartPoint.Y + _adorner.TopOffset - _adorner.ActualHeight / 2));
}
_adorner = null;
InvalidateVisual();
}
}