private void MoveNode( Node nodeToMove, Node targetNode, MoveOperation operation )
{
var siblings = (NodeCollection)targetNode.Parent.Children;
var dropPos = siblings.IndexOf( targetNode );
if ( operation == MoveOperation.MoveAfter )
{
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 )
{
siblings.Insert( dropPos, nodeToMove );
}
else
{
siblings.Add( nodeToMove );
}
}
IsDirty = true;
}
internal INode CreateChild( INode parent )
{
try
{
var node = new Node();
( ( Node )parent ).Children.Add( node );
return node;
}
finally
{
IsDirty = true;
}
}