Hi,
For this you can either use a property in your entity,say IsSelected,and bind the checkbox's(in the datatemplate of the treeviewitem) IsChecked property to it.
Or get the datatemplate from the treeview item,which can be obtained using the ItemsContainerGenerator and set the IsChecked property.
See this
link[
^]
Hope it helps :-D
Submit an article or tip