Assembly: System.Design (in system.design.dll)
true to force the update of design-time markup; otherwise, false.
The OnDataSourceChanged method connects to the current data source. If the current data source is different from the data source to which the control was previously connected, or forceUpdateView is true, the associated control is redrawn on the design surface.Notes to Inheritors: Override the OnDataSourceChanged method to perform additional actions that are required when the data source of the associated control changes. If you override the OnDataSourceChanged method, call the base implementation before performing other processing.
Other ResourcesIntroduction to ASP.NET Control Designers
Walkthrough: Creating a Basic Control Designer for a Web Server Control