/// <summary>
/// thx to @osicka from issue #84
///
/// e.g. original source is part of a popup (e.g. ComboBox drop down), the hit test needs to be done on the original source.
/// Because the popup is not attached to the visual tree of the sender.
/// This function test this by looping back from the original source to the sender and if it didn't end up at the sender stopped the drag.
/// </summary>
public static bool IsNotPartOfSender(object sender, InputEventArgs e)
{
var visual = e.OriginalSource as Visual;
if (visual == null)
{
return(false);
}
var hit = VisualTreeHelper.HitTest(visual, e.GetPosition((IInputElement)visual));
if (hit == null)
{
return(false);
}
else
{
var depObj = e.OriginalSource as DependencyObject;
if (depObj == null)
{
return(false);
}
var item = VisualTreeHelper.GetParent(depObj.FindVisualTreeRoot());
//var item = VisualTreeHelper.GetParent(e.OriginalSource as DependencyObject);
while (item != null && item != sender)
{
item = VisualTreeHelper.GetParent(item);
}
return(item != sender);
}
}
/// <summary>
/// Initializes a new instance of the DragInfo class.
/// </summary>
///
/// <param name="sender">
/// The sender of the mouse event that initiated the drag.
/// </param>
///
/// <param name="e">
/// The mouse event that initiated the drag.
/// </param>
public DragInfo(object sender, InputEventArgs e)
{
this.DragStartPosition = e.GetPosition((IInputElement)sender);
this.Effects = DragDropEffects.None;
//this.MouseButton = e.ChangedButton;
this.VisualSource = sender as UIElement;
this.DragDropCopyKeyState = DragDrop.GetDragDropCopyKeyState(this.VisualSource);
if (sender is ItemsControl)
{
var itemsControl = (ItemsControl)sender;
this.SourceGroup = itemsControl.FindGroup(this.DragStartPosition);
this.VisualSourceFlowDirection = itemsControl.GetItemsPanelFlowDirection();
var sourceItem = e.OriginalSource as UIElement; // If we can't cast object as a UIElement it might be a FrameworkContentElement, if so try and use its parent.
if (sourceItem == null && e.OriginalSource is FrameworkContentElement)
{
sourceItem = ((FrameworkContentElement)e.OriginalSource).Parent as UIElement;
}
UIElement item = null;
if (sourceItem != null)
{
item = itemsControl.GetItemContainer(sourceItem);
}
if (item == null)
{
if (DragDrop.GetDragDirectlySelectedOnly(VisualSource))
{
item = itemsControl.GetItemContainerAt(e.GetPosition(itemsControl));
}
else
{
item = itemsControl.GetItemContainerAt(e.GetPosition(itemsControl), itemsControl.GetItemsPanelOrientation());
}
}
if (item != null)
{
// Remember the relative position of the item being dragged
this.PositionInDraggedItem = e.GetPosition(item);
var itemParent = ItemsControl.ItemsControlFromItemContainer(item);
if (itemParent != null)
{
this.SourceCollection = itemParent.ItemsSource ?? itemParent.Items;
if (itemParent != itemsControl)
{
var tvItem = item as TreeViewItem;
if (tvItem != null)
{
var tv = tvItem.GetVisualAncestor <TreeView>();
if (tv != null && tv != itemsControl && !tv.IsDragSource())
{
return;
}
}
else if (itemsControl.ItemContainerGenerator.IndexFromContainer(itemParent) < 0 && !itemParent.IsDragSource())
{
return;
}
}
this.SourceIndex = itemParent.ItemContainerGenerator.IndexFromContainer(item);
this.SourceItem = itemParent.ItemContainerGenerator.ItemFromContainer(item);
}
else
{
this.SourceIndex = -1;
}
this.SourceItems = itemsControl.GetSelectedItems();
// Some controls (I'm looking at you TreeView!) haven't updated their
// SelectedItem by this point. Check to see if there 1 or less item in
// the SourceItems collection, and if so, override the control's
// SelectedItems with the clicked item.
if (this.SourceItems.Cast <object>().Count() <= 1)
{
this.SourceItems = Enumerable.Repeat(this.SourceItem, 1);
}
this.VisualSourceItem = item;
}
else
{
this.SourceCollection = itemsControl.ItemsSource ?? itemsControl.Items;
}
}
else
{
if (sender is UIElement)
{
this.PositionInDraggedItem = e.GetPosition((UIElement)sender);
}
}
if (this.SourceItems == null)
{
this.SourceItems = Enumerable.Empty <object>();
}
}
