Page.IsAsync Property
Gets a value indicating whether the page is processed asynchronously.
Namespace: System.Web.UI
Assembly: System.Web (in System.Web.dll)
Use the IsAsync property to determine whether the Web page is running in asynchronous mode. This information is useful if controls or code on the page need to modify their behavior depending on whether the page is asynchronous. For more information about asynchronous programming, see Asynchronous Operations (ADO.NET).
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.