RadTreeView with Checkbox

select Id, Name, RowId, IsChecked from table

Now, in NodeDataBound event handler you can access the database value for the particular node by

... = (e.Node.DataItem as DataRowView)["IsChecked"].ToString();

see this link:
http://www.telerik.com/help/aspnet-ajax/tree_servernodedatabound.html
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e.NodeBound.Checked = Convert.ToBoolean(dataSourceRow["IsChecked"]);
see this:
http://www.telerik.com/community/forums/aspnet/treeview/check-checkbox-in-radtreeview-when-databind.aspx