The ASP.NET 2.0 platform provides an entirely new approach to data binding, which eliminates the coding necessary for connecting a control to its underlying data source. Telerik RadTreeView employs this new way for accessing data, so that its data binding can be accomplished in a completely declarative manner using the new data source controls.

Declarative data source controls expose data from a back-end store (SQL database, middle-tier business object, XML file, XML Web Service) to data-bound UI control on a page. Data Source controls also provide new capabilities such as sorting, paging, caching, updating, inserting, and deleting data, which UI controls can automatically use of without any additional code.
Data Source Controls
Data source controls are not rendered, but instead represent a particular back-end data store. ASP.NET 2.0 includes the following server controls out-of-the-box: SqlDataSource, ObjectDataSource, AccessDataSource, SiteMapSource, XmlDataSource.

Currently RadTreeView supports the following data source controls:

SiteMapSource - enables binding to the hierarchy exposed by an ASP.NET 2.0 site navigation provider.
The SiteMapDataSource control is associated to a data-bound control through the control's DataSourceID property.
XmlDataSource - Enables binding to an XML file or document.
XmlDataSource supports a DataFile property for specifying the path to an XML data file to be used as input. You may also specify a TranformFile property to apply an XSLT transformation to the data and an XPath property for specifying a subset of nodes to expose from the data source.