Hi Balaram Barange,
I modified the mentioned solution to meet your requirement. Basically I iterate over the "Items" collection of the BusinessItem on CollectionChanged event and check whether all child items are collapsed. If yes, I se boolean property from to true in the BusinesItem. This bool property is bind to the ExpanderStyle property of the RadtreeViewitem via Converter. Please let us know if this approach satisfies you.
All the best,
the Telerik team
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