Returns a value that indicates whether the trigger was activated.
Assembly: System.Web.Extensions (in System.Web.Extensions.dll)
Control developers can override the property to provide custom logic for determining whether the trigger was activated. To see your custom trigger appear at design time in the <Triggers> element of the UpdatePanel control, you can add an @ Register directive on the page or in the controls section of the Web.config file.
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.