I am sending you a sample project demonstrating how to transform many-to-many relationship into parent-child relationship using WCF Ria Services and Load On demand. The trick is that I am setting the ItemsSource collection of the expanded RadTreeViewItem in the LoadOnDemand handler. I have Categories ---> Product <----Suppliers relationship from the standard NorthWind database
. The Products table holds the CategoryID and SupplierID. The solution demonstrates how to show Categories on a root level and Suppliers for the particular category in the second level. You should be able to get the idea how to create the third level using LOD feature again. Please examine it and let me know if it fits in your scenario.
the Telerik team
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