/// <summary>
/// New drop target identified
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void PreviewDragEnter(object sender, DragEventArgs e)
{
e.Handled = true;
e.Effects = DragDropEffects.None;
var itemsControl = (ItemsControl)sender;
// Do not allow if sorted.
if (!DragUtilities.CanReorderCollectionView(itemsControl))
{
return;
}
if (e.Data.GetDataPresent(this.ItemTypeKey))
{
DragInfo data = e.Data.GetData(this.ItemTypeKey) as DragInfo;
if (data != null)
{
if (!data.AllowOnlySelf || itemsControl == data.Source)
{
var allowedEffects = e.AllowedEffects;
if (itemsControl == data.Source && !this.AllowSelf)
{
allowedEffects = DragDropEffects.None;
}
else if (this.DropEnter != null)
{
DragDropEventArgs de = new DragDropEventArgs(data.Source, itemsControl, data.Data)
{
AllowedEffects = allowedEffects
};
this.DropEnter(this, de);
allowedEffects = de.AllowedEffects;
if (de.Cancel)
{
return;
}
}
this.InitializeDragAdorner(itemsControl, data.Data, e.GetPosition(itemsControl));
e.Effects = GetDropEffectType(allowedEffects, e.KeyStates);
if (e.Effects != DragDropEffects.None)
{
this.InitializeInsertAdorner(itemsControl, e);
}
}
}
}
}
/// <summary>
/// Display the drag indicator
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void PreviewMouseMove(object sender, MouseEventArgs e)
{
if (this._isMouseDown)
{
var itemsControl = (ItemsControl)sender;
Point currentPosition = e.GetPosition(itemsControl);
if ((this._isDragging == false) && (Math.Abs(currentPosition.X - this._dragStartPosition.X) > SystemParameters.MinimumHorizontalDragDistance) ||
(Math.Abs(currentPosition.Y - this._dragStartPosition.Y) > SystemParameters.MinimumVerticalDragDistance))
{
// Do not allow if sorted and we only allow this element as
// the drop target.
if (!DragUtilities.CanReorderCollectionView(itemsControl) &&
this.AllowOnlySelf)
{
return;
}
this.DragStarted(itemsControl);
}
}
}
