XtraTreelist: Operation is not valid due to the current state of the object - DragDrop

I have an xtraTreeList with both keyFieldName and ParentFieldName are set

in some开发者_如何学编程 cases while dragDrop nodes to each other i got the exception as a messageBox

"Operation is not valid due to the current state if the object"

and for that the parentField not updated!

the exception is vague, any suggestions?

Could you please post a callstack to this error. I am sure, that the exception is not raised by the XtraTreeList but is raised by its DataSource. Anyway, this will give us a starting point in an attempt to find the cause of this problem.

If you are using linq to sql, then make sure the parent is not loop-linked within the table, as this will require the node sorting to update the entity relation, which it does not do by itself (devex treelist)...