private void MoveNode(NodeWriteAccess nodeToMove, NodeWriteAccess targetNode, DropLocation operation)
{
var siblings = targetNode.Siblings;
var dropPos = siblings.IndexOf(targetNode);
if (operation == DropLocation.After)
{
dropPos++;
}
if (siblings.Contains(nodeToMove))
{
var oldPos = siblings.IndexOf(nodeToMove);
if (oldPos < dropPos)
{
// ObservableCollection first removes the item and then reinserts which invalidates the index
dropPos--;
}
siblings.Move(oldPos, dropPos);
}
else
{
if (dropPos < siblings.Count)
{
ChangeParent(nodeToMove, n => siblings.Insert(dropPos, n), targetNode.GetParent());
}
else
{
ChangeParent(nodeToMove, n => siblings.Add(n), targetNode.GetParent());
}
}
}
private void ChangeParent(NodeWriteAccess nodeToMove, Action <NodeWriteAccess> insertionOperation, NodeWriteAccess newParent)
{
var oldParent = nodeToMove.GetParent();
oldParent.Children.Remove(nodeToMove);
insertionOperation(nodeToMove);
nodeToMove.SetParent(newParent.Node);
}
public void ApplyDrop(NodeDropRequest request)
{
var droppedNode = new NodeWriteAccess(request.DroppedNode);
var dropTarget = new NodeWriteAccess(request.DropTarget);
if (request.DropTarget == myRoot)
{
ChangeParent(droppedNode, n => myRoot.Children.Add(n), myRoot);
}
else if (request.Location == DropLocation.Before || request.Location == DropLocation.After)
{
MoveNode(droppedNode, dropTarget, request.Location);
}
else
{
ChangeParent(droppedNode, n => dropTarget.Children.Add(n), dropTarget);
}
}
public bool Contains(NodeWriteAccess node)
{
return(myCollection.Contains(node.Node));
}
public int IndexOf(NodeWriteAccess node)
{
return(myCollection.IndexOf(node.Node));
}
public void Remove(NodeWriteAccess node)
{
(( IList )myCollection).Remove(node.Node);
}
public void Insert(int pos, NodeWriteAccess node)
{
(( IList )myCollection).Insert(pos, node.Node);
}
public void Add(NodeWriteAccess node)
{
(( IList )myCollection).Add(node.Node);
}
public DragDropBehavior(INode root)
{
Contract.RequiresNotNull(root, "root");
myRoot = new NodeWriteAccess(root);
}
