Gets or sets an object used to uniquely identify an asynchronous operation.
Assembly: System (in System.dll)
If your class supports multiple asynchronous methods or multiple invocations of a single asynchronous method, clients will need a way to determine which asynchronous task is raising events. Your MethodNameAsync method should take a parameter of type Object that will act as a task ID. You will use this task ID when you call the AsyncOperationManager.CreateOperation, method and this will associate the client's task ID with a particular invocation of your asynchronous operation. This task ID is made available to your implementation through the property.
Client code must be careful to provide a unique value for the property. Non-unique task IDs may cause your implementation to report progress and other events incorrectly. Your code should check for a non-unique task ID and raise an ArgumentException if one is detected.
The following code example demonstrates using to track the lifetime of asynchronous operations. This code example is part of a larger example provided for the System.ComponentModel.AsyncOperationManager class.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.