private static void OnDataObjectChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var attached = DragDropManager.GetIsDragSourceAttached(d);
if (!attached)
{
DragDropManager.SetIsDragSourceAttached(d, true);
(( UIElement )d).PreviewMouseLeftButtonDown += (s, args) =>
{
var _startPoint = args.GetPosition(null);
DragDropManager.SetStartPoint(d, _startPoint);
};
/*
* We cannot use "MouseLeftButtonDown" because on the
* TreeView control is never fired, maybe is handled by
* someone else in the processing pipeline.
*/
//( ( UIElement )d ).MouseLeftButtonDown += ( s, args ) =>
//{
// var _startPoint = args.GetPosition( null );
// DragDropManager.SetStartPoint( d, _startPoint );
//};
(( UIElement )d).MouseMove += (s, args) =>
{
var isDragging = DragDropManager.GetIsDragging(d);
if (args.LeftButton == MouseButtonState.Pressed && !isDragging)
{
var position = args.GetPosition(null);
var _startPoint = DragDropManager.GetStartPoint(d);
if (Math.Abs(position.X - _startPoint.X) > SystemParameters.MinimumHorizontalDragDistance ||
Math.Abs(position.Y - _startPoint.Y) > SystemParameters.MinimumVerticalDragDistance)
{
StartDrag(d, args);
}
}
};
}
}
static void StartDrag(DependencyObject d, MouseEventArgs e)
{
var sourceItem = DragDropManager.FindDragContainer(( DependencyObject )e.OriginalSource);
DragDropManager.SetIsDragging(d, true);
var obj = DragDropManager.GetDataObject(sourceItem);
var objType = DragDropManager.GetDataObjectType(sourceItem);
DataObject data = null;
if (String.IsNullOrEmpty(objType))
{
data = new DataObject(obj.GetType(), obj);
}
else
{
data = new DataObject(objType, obj);
}
var de = DragDrop.DoDragDrop(d, data, DragDropEffects.Move);
DragDropManager.SetIsDragging(d, false);
}
private static void OnOnDropCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var attached = DragDropManager.GetIsDropTargetAttached(d);
if (!attached)
{
DragDropManager.SetIsDropTargetAttached(d, true);
var ui = ( UIElement )d;
ui.AllowDrop = true;
var ctrl = ui as Control;
if (ctrl != null)
{
var bkg = ctrl.GetValue(ItemsControl.BackgroundProperty);
if (bkg == null)
{
ctrl.SetValue(ItemsControl.BackgroundProperty, Brushes.Transparent);
}
}
ui.DragEnter += (s, args) =>
{
var os = ( DependencyObject )args.OriginalSource;
var command = DragDropManager.FindDragEnterCommand(os);
if (command != null)
{
var dropTarget = DragDropManager.FindDropTarget(os);
var cmdArgs = new DragEnterArgs(
args.Data,
args.KeyStates,
dropTarget,
args.AllowedEffects);
if (command.CanExecute(cmdArgs))
{
command.Execute(cmdArgs);
}
}
};
ui.DragLeave += (s, args) =>
{
var os = ( DependencyObject )args.OriginalSource;
var command = DragDropManager.FindDragLeaveCommand(os);
if (command != null)
{
var dropTarget = DragDropManager.FindDropTarget(os);
var cmdArgs = new DragLeaveArgs(
args.Data,
args.KeyStates,
dropTarget,
args.AllowedEffects);
if (command.CanExecute(cmdArgs))
{
command.Execute(cmdArgs);
}
}
};
ui.DragOver += (s, args) =>
{
var os = ( DependencyObject )args.OriginalSource;
var command = DragDropManager.FindDropCommand(os);
if (command != null)
{
var dropTarget = DragDropManager.FindDropTarget(os);
Point position = new Point(0, 0);
if (os is IInputElement)
{
position = args.GetPosition(( IInputElement )os);
}
var cmdArgs = new DragOverArgs(
args.Data,
args.KeyStates,
dropTarget,
args.AllowedEffects,
position);
var result = command.CanExecute(cmdArgs);
if (!result)
{
args.Effects = cmdArgs.Effects;
args.Handled = true;
}
}
else
{
args.Effects = args.AllowedEffects;
args.Handled = true;
}
};
ui.Drop += (s, args) =>
{
var os = ( DependencyObject )args.OriginalSource;
var command = DragDropManager.FindDropCommand(os);
if (command != null)
{
var dropTarget = DragDropManager.FindDropTarget(os);
Point position = new Point(0, 0);
if (os is IInputElement)
{
position = args.GetPosition(( IInputElement )os);
}
var cmdArgs = new DropArgs(args.Data, args.KeyStates, dropTarget, position);
command.Execute(cmdArgs);
}
};
}
}
