AsyncCompletedEventArgs::UserState Property
Gets the unique identifier for the asynchronous task.
Namespace: System.ComponentModel
Assembly: System (in System.dll)
Property Value
Type: System::ObjectAn object reference that uniquely identifies the asynchronous task; otherwise, nullptr 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 have to 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 how to use UserState to track the lifetime of asynchronous operations. The local variable used to store the values tracked by UserState is named taskID in this example. This code example is part of a larger example provided for the System.ComponentModel::AsyncOperationManager class.
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