Кратко: Treeview for ASP.NET (client model, ADO.NET, load-on-demand, drag-and-drop, ...).
9Rays.Net TreeView for ASP.NET - 9Rays TreeView for ASP.NET (FlyTreeView) is a dynamic treeview control. Native ASP.NET control, features visual designers, native .net DataBinding to any ADO.NET source (DataSet, DataReader, arrays, and IList implementations, etc.), drag-and-drop operations, full ASP.NET viewstate support, highly customizable styles and behaviors, XML node sources to enable load on demand, FlyNodeSet control to provide on demand nodes renderring and loading (ex. file system) , checkboxes, multiple postback events (select, deselect, expand, collapse, check, uncheck), server side handling of all client events, comprehensive client object model, context menu, flexible licensing options.