The System.Web.UI.WebControls.BaseDataList control uses the BaseDataList.RequiresDataBinding property to determine whether the control needs to call the BaseDataList.DataBind method to bind to its specified data source.

Each time the set accessor is called on either the BaseDataList.DataSource, the BaseDataList.DataSourceID, or the BaseDataList.DataMember property to change the data source after the BaseDataList.OnInit(EventArgs) method has already been called, ASP.NET automatically sets the value of the BaseDataList.RequiresDataBinding property to true. The value of the BaseDataList.RequiresDataBinding property is also set to true when the HierarchicalDataBoundControl.OnDataSourceChanged(object, EventArgs) method is called.

ASP.NET automatically sets the value of the Repeater.RequiresDataBinding property to false immediately after the BaseDataList.DataBind method has been called.