如果并行任务抛出异常则取消任务 [英] Canceling task if a parallel task throw an exception

问题描述

我有两个共享相同取消令牌的并行任务，客户端要求两个结果列表，例如:

I have two parallel tasks that share the same cancellation token, the client asks for two lists of result like:

class ResponseDTO
{
    public IEnumerable<Entity1> Entity1List { get; set; }
    public IEnumerable<Entity2> Entity2List { get; set; }
}

这两个请求是同时计算和依赖的，因此如果列表中的一个没有结果，则无需等待另一个结果.

The two requests are calculated simultaneously and depended, so if one of the list is has no result there no need to wait for the other result.

var cts = new CancellationTokenSource();
var token = cts.Token;

Task task1 = new Task(() =>
{
    //fetch Entity1 results into entity1List

    if (!entity1List.Any())
    {
        cts.Cancel();
    }
    else
    {
        responseDTO.Entity1List = entity1List;
    }
}, token);

Task task2 = new Task(() =>
{
    //fetch Entity2 results into entity2List

    if (!entity2List.Any())
    {
        cts.Cancel();
    }
    else
    {
        responseDTO.Entity2List = entity2List;
    }
}, token);

task1.Start();
task2.Start();

try
{
    Task.WaitAll(new[] { task1, task2 }, token);
}
catch (OperationCanceledException oce)
{
    return responseDTO;
}
catch (AggregateException ae)
{
    foreach (var ex in ae.InnerExceptions)
        //Log the exception
    return responseDTO;
}

return responseDTO;

如果任务返回空列表，取消工作正常.

In case of the tasks has returned an empty list the canceling works fine.

我的问题是:如果另一个任务抛出一般异常，如何取消其中一个任务?

My question is: how to cancel one of the tasks if the other one threw a general exception?

推荐答案

已通过 @noobed 评论解决.

Solved with @noobed comment.

try
{
    //fetch Entity1 results into entity1List
}
catch
{
    cts.Cancel();
}

在一般异常的情况下，它会被catch，并且可以使用cancel调用cts.

In case of general exception it will be catch, and the cts can be called with cancel.

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