/// <summary>
/// Drop started
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void PreviewDrop(object sender, DragEventArgs e)
{
var itemsControl = (ItemsControl)sender;
this.DestroyAdorners();
e.Handled = true;
if (e.Data.GetDataPresent(this.ItemTypeKey))
{
int index = FindInsertionIndex(itemsControl, e);
DragInfo data = e.Data.GetData(this.ItemTypeKey) as DragInfo;
if (data != null && (!data.AllowOnlySelf || itemsControl == data.Source))
{
var allowedEffects = e.AllowedEffects;
if (this.DropInitiated != null)
{
DragDropEventArgs de = new DragDropEventArgs(data.Source, itemsControl, data.Data, index)
{
AllowedEffects = allowedEffects
};
this.DropInitiated(this, de);
allowedEffects = de.AllowedEffects;
if (de.Cancel)
{
e.Effects = DragDropEffects.None;
return;
}
}
object itemToAdd = data.Data;
e.Effects = GetDropEffectType(allowedEffects, e.KeyStates);
if (DragUtilities.DoesItemExists(itemsControl, itemToAdd) &&
(e.Effects == DragDropEffects.Move ||
(e.Effects & DragDropEffects.Move) > 0 && (e.KeyStates & DragDropKeyStates.ControlKey) > 0))
{
DragUtilities.RemoveItem(itemsControl, itemToAdd);
// Recalc our position based on the removal
index = FindInsertionIndex(itemsControl, e);
}
DragUtilities.AddItem(itemsControl, itemToAdd, index);
DragUtilities.SelectItem(itemsControl, index);
}
else
{
e.Effects = DragDropEffects.None;
}
}
else
{
e.Effects = DragDropEffects.None;
}
}
/// <summary>
/// This starts the drag operation from the given ItemsControl
/// </summary>
/// <param name="itemsControl"></param>
private void DragStarted(ItemsControl itemsControl)
{
DragDropEffects allowedEffects = DragDropEffects.Copy | DragDropEffects.Move;
if (this.DragInitiated != null)
{
var dde = new DragDropEventArgs(itemsControl, null, this._data)
{
AllowedEffects = allowedEffects
};
this.DragInitiated(this, dde);
if (dde.Cancel)
{
this.ResetState();
return;
}
allowedEffects = dde.AllowedEffects;
}
UIElement draggedItemContainer = DragUtilities.GetItemContainerFromPoint(itemsControl, this._dragStartPosition);
this._isDragging = true;
DataObject dObject = new DataObject(this.ItemTypeKey, new DragInfo {
Data = this._data, Source = itemsControl, AllowOnlySelf = this.AllowOnlySelf
});
DragDropEffects e = DragDrop.DoDragDrop(itemsControl, dObject, allowedEffects);
if ((e & DragDropEffects.Move) != 0)
{
if (draggedItemContainer != null)
{
int dragItemIndex = itemsControl.ItemContainerGenerator.IndexFromContainer(draggedItemContainer);
DragUtilities.RemoveItem(itemsControl, dragItemIndex);
}
else
{
DragUtilities.RemoveItem(itemsControl, this._data);
}
}
this.ResetState();
}