winforms datasource PositionChanged validate previous object

Question

In my appplication I have a ListBox with items in the left panel and in the right panel I have the item details. If user click a new item in the listbox and if the current item was changed I want to ash the user if he wants to save changes or discard them.

The way I am doing now is on SelectedIndexChanged of the listbox to remember previous position and move the current element in the datasource accordingly.

Do you know any other way to validate the current object before data source position change? I wanted something like PositionChanging ... where I can cancel the operation.

Thanks a lot, Radu