AsyncCompletedEventArgs.UserState Property
Gets the unique identifier for the asynchronous task.
Assembly: System (in System.dll)
Property Value
Type: System.ObjectAn object reference that uniquely identifies the asynchronous task; otherwise, a null reference (Nothing in Visual Basic) if no value has been set.
If a class supports multiple asynchronous methods, or multiple invocations of a single method, you can determine which task raised the MethodNameCompleted event by checking the value of the UserState property. Your code will need track these tokens, known as task IDs, as their corresponding asynchronous tasks start and complete.
The value of this property is set during the original call to the asynchronous method that started the task.
The following code example demonstrates using an AsyncOperation to track the lifetime of asynchronous operations. This code example is part of a larger example provided for the System.ComponentModel.AsyncOperationManager class.
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.
