知道哪个 CancellationToken 在 CreateLinkedTokenSource 中失败以评估奇怪的 cancellationRequested 行为

Question

我有以下代码

Class Class1
{
    Class2 class2 = new Class2();
    CancellationToken first = new CancellationToken();
    CancellationToken second = new CancellationToken();
    CancellationTokenSource cts=
              CancellationTokenSource.CreateLinkedTokenSource(first, second))
    class2.OpenSocketAndRead(cts.Token);
}

Class Class2
{
   public void OpenSocketAndRead(CancellationToken ct)
   {
       try
       {
          await websocket.ReceiveAsync(new ArraySegment<byte>(buffer, receivedBytes, availableBytes), ct).ConfigureAwait(false);
       }
       catch (WebSocketException e)
       {
           ct.ThrowIfCancellationRequested();
           var message = this.ConstructErrorMessage("Error during read.", ct);
           throw new CustomException(message);
       }
   }

   private string ConstructErrorMessage(String m, CancellationToken ct)
   {
       StringBuffer sb = new StringBuffer();
       sb.append(m);
       if(ct.IsCancellationRequested)
       {
           sb.append("WHICH TOKEN FAILED");
       }
   } 
}

我遇到了这种奇怪的行为，其中 ct 没有抛出并且流来到 ConstructErrorMessage，其中 ct.IsCancellationRequested 评估为真。 Websocket 错误代码是 ConnectionClosedPrematurely。

我想知道哪个令牌在 ConstructErrorMessage 中失败以及为什么 ThrowIfCancellationRequested 没有执行。

Answer 1

I experienced this weird behavior where ct didnotthrow and the flow came to ConstructErrorMessage where ct.IsCancellationRequested evaluates to true.

这完全有可能 - 这意味着 CancellationToken 在调用 ThrowIfCancellationRequested 之后和调用 IsCancellationRequested.

之前被取消了

I want to know which token failed

这在一般情况下是不可能的，因为链接令牌。但是，您的代码可以检查哪些标记被取消，并且出于所有实际考虑，这通常就足够了。

知道哪个 CancellationToken 在 CreateLinkedTokenSource 中失败以评估奇怪的 cancellationRequested 行为

Know which CancellationToken failed in CreateLinkedTokenSource to evaluate weird cancellationRequested behavior

c#

cancellation

cancellationtokensource

cancellation-token