/// <summary>
/// Determine the proper insertion index
/// </summary>
/// <param name="itemsControl"></param>
/// <param name="e"></param>
/// <returns></returns>
private static int FindInsertionIndex(ItemsControl itemsControl, DragEventArgs e)
{
UIElement dropTargetContainer = DragUtilities.GetItemContainerFromPoint(itemsControl, e.GetPosition(itemsControl));
if (dropTargetContainer != null)
{
int index = itemsControl.ItemContainerGenerator.IndexFromContainer(dropTargetContainer);
return(DragUtilities.IsPointInTopHalf(itemsControl, e) ? index : index + 1);
}
return(itemsControl.Items.Count);
}
/// <summary>
/// Initialize the insertion point marker
/// </summary>
/// <param name="itemsControl"></param>
/// <param name="e"></param>
private void InitializeInsertAdorner(ItemsControl itemsControl, DragEventArgs e)
{
if (this._insertAdorner == null && this.ShowInsertAdorner)
{
UIElement itemContainer = DragUtilities.GetItemContainerFromPoint(itemsControl, e.GetPosition(itemsControl));
if (itemContainer != null)
{
this._insertAdorner = new InsertAdorner(DragUtilities.IsPointInTopHalf(itemsControl, e),
DragUtilities.IsItemControlOrientationHorizontal(itemsControl),
itemContainer, AdornerLayer.GetAdornerLayer(itemsControl), itemsControl);
}
}
}
/// <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();
}