Canceling managed threads
Canceling asynchronous work in .NET is based on the use of a cancellation token. A token is a simple object that is used to signal that a cancellation request has been made to another thread. The CancellationTokenSource object manages these requests and contains a token. If you want to cancel several operations with the same trigger, the same token should be provided to all of the threads to be canceled.
A CancellationTokenSource instance has a Token property to access the CancellationToken property and pass it to one or more asynchronous operations. The request to cancel can only be made from the CancellationTokenSource object. The CancellationToken property provided to the other operations receives the signal to cancel but cannot initiate a cancellation.
CancellationTokenSource implements the IDisposable interface, so be sure to call Dispose when you are freeing your managed resources. A using statement or block to automatically dispose of the token...