The TreeView control can also be bound to data. You can use either of two methods to bind the TreeView control to the appropriate data source type:

• The TreeView control can use any data source control that implements the IHierarchicalDataSource interface, such as an XmlDataSource control or a SiteMapDataSource control. To bind to a data source control, set the DataSourceID property of the TreeView control to the ID value of the data source control. The TreeView control automatically binds to the specified data source control. This is the preferred method to bind to data.

• The TreeView control can also be bound to an XmlDocument object or a DataSet object with relations. To bind to one of these data sources, set the DataSource property of the TreeView control to the data source, and then call the DataBind method.

When binding to a data source where each data item contains multiple properties (such as an XML element with several attributes), a node displays the value that is returned by the ToString method of the data item, by default. In the case of an XML element, the node displays the element name, which shows the underlying structure of the tree but is not very useful otherwise. You can bind a node to a specific data item property by specifying tree node bindings using the DataBindings collection. The DataBindings collection contains TreeNodeBinding objects that define the relationship between a data item and the node that it is binding to. You can specify the criteria for binding and the data item property to display in the node. For more information on tree node bindings, see TreeNodeBinding.