This member overrides Control.CreateControlCollection(), and more complete documentation might be available in that topic.
Returns the collection of all controls that are contained in the UpdatePanel control.
Assembly: System.Web.Extensions (in System.Web.Extensions.dll)
The method is used by control developers.
Because this method is protected and sealed, it is visible to classes that inherit from the UpdatePanel class, but it cannot be overridden. This method overrides the base implementation to return a specialized ControlCollection object that throws an InvalidOperationException when the Add, AddAt, Clear, Remove, or RemoveAt method of the ControlCollection class is invoked. To change the content of the UpdatePanel control, modify the child controls of the ContentTemplateContainer property.