[How Do I:] Update Multiple Regions of a Page with ASP.NET AJAX?
In this video we learn that the ASP.NET AJAX UpdatePanel control provides two properties that you may use to update multiple regions of a Web page in response to a single client-side event. The UpdateMode property may be set to Always, in which case the panel will always update during a post back, or set to Conditional, in which case the panel will only update in response to specific events. The Triggers collection property allows you to specify those events that will cause the panel to update. Used together these properties allow multiple UpdatePanel controls to update in response to the same event trigger.