private bool IsValidDropTarget(UIElement target)
{
FrameworkElement dropTarget;
if (target == null)
{
SwitchDropTarget(null);
Console.WriteLine("IsValidDropTarget ====> target is NULL");
return(false);
}
TreeViewItem container = GetNearestContainer(target);
if (container == null)
{
SwitchDropTarget(null);
Console.WriteLine("IsValidDropTarget ====> container is NULL");
return(false);
}
Node_Base dataTarget = container.Header as Node_Base;
if (dataTarget == null)
{
SwitchDropTarget(null);
Console.WriteLine("IsValidDropTarget ====> dataTarget is null");
return(false);
}
/*
* if (CurrentDropTarget != null)
* CurrentDropTarget.DropArea = Node_Base.enItemDropArea.None;
*
* CurrentDropTarget = source;
* CurrentDropTarget.DropArea = targetDropArea_;
*/
#region check PART_TopDropArea
dropTarget = FindAncestorByName(target, "PART_TopDropArea");
if (dropTarget != null)
{
dataTarget.DropArea = Node_Base.enItemDropArea.Top;
Console.WriteLine("IsValidDropTarget ====> Hovering on PART_TopDropArea");
SwitchDropTarget(dataTarget);
return(true);
}
#endregion
#region check PART_BottomDropArea
dropTarget = FindAncestorByName(target, "PART_BottomDropArea");
if (dropTarget != null)
{
dataTarget.DropArea = Node_Base.enItemDropArea.Bottom;
Console.WriteLine("IsValidDropTarget ====> Hovering on PART_BottomDropArea");
SwitchDropTarget(dataTarget);
return(true);
}
#endregion
//TreeViewItem container = GetNearestContainer(target);
if (container == null)
{
Console.WriteLine("IsValidDropTarget ====> container is NULL");
SwitchDropTarget(null);
return(false);
}
if (sourceNode_.Children.Contains(targetNode_))
{
Console.WriteLine("IsValidDropTarget ====> cannot drop parent on child");
SwitchDropTarget(null);
return(false);
}
//Node_Base dataTarget = container.Header as Node_Base;
if (sourceNode_ == dataTarget)
{
Console.WriteLine("IsValidDropTarget ====> itself");
SwitchDropTarget(null);
return(false);
}
if (dataTarget is Node_Cell)
{
Console.WriteLine("IsValidDropTarget ====> cannot drop over cell");
SwitchDropTarget(null);
return(false);
}
if (dataTarget is Node_Group)
{
dataTarget.DropArea = Node_Base.enItemDropArea.Center;
SwitchDropTarget(dataTarget);
dataTarget.IsExpanded = true;
}
else
{
dataTarget.DropArea = Node_Base.enItemDropArea.None;
SwitchDropTarget(null);
}
Console.WriteLine("IsValidDropTarget ====> Hovering on " + dataTarget.Name);
return(dataTarget is Node_Group);
}
private void TreeView_MouseMove(object sender, MouseEventArgs e)
{
if (e.LeftButton != MouseButtonState.Pressed)
{
return;
}
Point currentPosition = e.GetPosition(TheTreeView);
// Note: This should be based on some accessibility number and not just 2 pixels
if ((Math.Abs(currentPosition.X - _lastMouseDown.X) > 5.0) ||
(Math.Abs(currentPosition.Y - _lastMouseDown.Y) > 5.0))
{
Node_Base selectedItem = (Node_Base)TheTreeView.SelectedItem;
sourceNode_ = selectedItem;
Console.WriteLine("TreeView_MouseMove >>> selectedItem = " + selectedItem.Name);
if (selectedItem == null)
{
return;
}
//TreeViewItem container = (TreeViewItem)(TheTreeView.ItemContainerGenerator.ContainerFromIndex(TheTreeView.Items.CurrentPosition));
TreeViewItem container = (TreeViewItem)(TheTreeView.ItemContainerGenerator.ContainerFromItem(sourceNode_));
container = GetTreeViewItem(e.GetPosition(TheTreeView));
if (container == null)
{
return;
}
IsDragInProgress = true;
DragDropEffects finalDropEffect = DragDrop.DoDragDrop(container, selectedItem, DragDropEffects.Move);
IsDragInProgress = false;
// check if we are trying to drop a node onto one of its children
if (selectedItem.ContainsNode(targetNode_))
{
return;
}
if (selectedItem == targetNode_)
{
return;
}
// verificare che il target non sia figlio del selectedItem
if ((finalDropEffect == DragDropEffects.Move) && (targetNode_ != null))
{
#region A Move drop was accepted
selectedItem.Parent.Children.Remove(selectedItem);
switch (targetDropArea_)
{
case Node_Base.enItemDropArea.Top:
targetNode_.Parent.Children.Insert(targetNode_.Index, selectedItem);
break;
case Node_Base.enItemDropArea.Center:
targetNode_.Children.Add(selectedItem);
break;
case Node_Base.enItemDropArea.Bottom:
targetNode_.Parent.Children.Insert(targetNode_.Index + 1, selectedItem);
break;
default:
break;
}
SelectNode(selectedItem);
#endregion
}
root_.UpdateIndexes();
sourceNode_ = null;
targetNode_ = null;
IsDragInProgress = false;
}
}