I am using RadTreeListView control to display data as a hierarchical view. I am binding my entity collection to the control using ItemSource, and my entity collection is of type ObservableCollection<T>. Whenever some data is changed in the source collection, i am performing an ItemSource again on the control. This is leading to losing all the expand/collapse state of the control. Thats is, as soon as I bind the new data (ItemSource), it updated the data but closes the expand/collapse state. How can I maintain the expand/collapse state of control even after ItemSource.