[C#] 实现可设置超时的 Task

前言

如何实现支持超时的 Task ？

关键点： Task.WhenAny

实现

一个扩展方法就可以搞定。

// 有返回值
public static async Task<TResult> TimeoutAfter<TResult>(this Task<TResult> task, TimeSpan timeout)
{
using (var timeoutCancellationTokenSource = new CancellationTokenSource())
{
var completedTask = await Task.WhenAny(task, Task.Delay(timeout, timeoutCancellationTokenSource.Token));
if (completedTask == task)
{
timeoutCancellationTokenSource.Cancel();
return await task; // Very important in order to propagate exceptions
}
else
{
throw new TimeoutException("The operation has timed out.");
}
}
}// 无返回值
public static async Task TimeoutAfter(this Task task, TimeSpan timeout)
{
using (var timeoutCancellationTokenSource = new CancellationTokenSource())
{
var completedTask = await Task.WhenAny(task, Task.Delay(timeout, timeoutCancellationTokenSource.Token));
if (completedTask == task)
{
timeoutCancellationTokenSource.Cancel();
await task; // Very important in order to propagate exceptions
}
else
{
throw new TimeoutException("The operation has timed out.");
}
}
}


参考

c# - Asynchronously wait for Task to complete with timeout - Stack Overflow