CancellationTokenSource source1 = new CancellationTokenSource();

//现在要让source1取消
//source1.Cancel();

CancellationTokenSource source2 = new CancellationTokenSource();

source2.Cancel();

var combineSource = CancellationTokenSource.CreateLinkedTokenSource(source1.Token, source2.Token);

Console.WriteLine("s1={0}  s2={1}  s3={2}", source1.IsCancellationRequested,
																				 source2.IsCancellationRequested,
																				 combineSource.IsCancellationRequested);
//s1=False  s2=True  s3=True
Console.Read();