When you override the BaseDataBoundControlDesigner.DataBind(System.Web.UI.WebControls.BaseDataBoundControl) method in a designer that is derived from the System.Web.UI.Design.WebControls.BaseDataBoundControlDesigner class, perform the necessary actions to set up the data-bound control so that when the design-time markup is retrieved, the control renders properly. Typically, you will associate a design-time data source rather than the live data source, for performance reasons.