如果循环花费太多时间，程序必须自动知道。 [英] Program must know automatically if a loop takes too much time.

问题描述

说我有一个for循环。如果在for循环的一个循环中花费的时间超过10分钟，我希望程序自动继续for循环。我想运行一些额外的命令来清理代码。任何想法如何实现这个？



即使循环中断我也可以管理。



FYI ，

我的问题是我的服务从SQL服务器中获取一行并在其上运行一些逻辑，但逻辑有时会进入无限循环。因此，我需要手动从SQL服务器中删除该行并重新启动该服务。



对不起英文不好

Say i have a for loop. I want the program to automatically 'continue' the for loop if the time spent inside one loop of the for loop is more than say 10 minutes. I want to run some additional commands to clean up the code too. Any Ideas how I can implement this ?

I can manage even if the loop breaks.

FYI,
My problem is that my service picks up a row from an SQL server and runs some logics on it but the logics sometimes goes into an infinite loop. Due to this I need to manually remove the row from the SQL server and restart the service.

Sorry for Bad English

推荐答案

A）
您可以尝试这种方法：

A) You could try this approach:

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Diagnostics;

class Program
{
    static long counter = 0;

    static void DoLongRunningTask(CancellationToken token)
    {
        token.ThrowIfCancellationRequested();

        Stopwatch stopwatch = new Stopwatch();
        stopwatch.Start();

        while (true)
        {
            Console.Write("{0}\r",counter++);
            if (token.IsCancellationRequested)
            {
                stopwatch.Stop();
                Console.WriteLine("\nCanceled. Cleaning up. Time elapsed: {0}", stopwatch.Elapsed);
                token.ThrowIfCancellationRequested();
            }
        }
    }

    static void Main()
    {
        var tokenSource = new CancellationTokenSource();
        var token = tokenSource.Token;
        var task = new Task(() => DoLongRunningTask(token), token);

        Console.Write("Task ");
        task.Start();
        tokenSource.CancelAfter(10000);
        Console.Write("started and should run 10 seconds\n");

        try  { task.Wait(); }
        catch { }

        Console.WriteLine("Status:      {0}", task.Status);
        Console.WriteLine("IsCanceled:  {0}", task.IsCanceled);
        Console.WriteLine("IsCompleted: {0}", task.IsCompleted);

        task.Dispose();

        Console.WriteLine("Finished. Press any key.");
        Console.ReadKey();
    }
}

请注意，这不是蛮力取消。它不会杀死任务，它需要整洁的完成。因此，如果你被阻止在一个操作中 - 让我们在这个意义上称它为原子 - 这对你没有帮助。 （来源： http://www.blackwasp.co.uk/TaskCancellation_2.aspx [ ^ ]）



但是，您不能以这种方式等待任务完成，在此期间您可以在服务中执行任何其他操作。



一篇有趣的文章，但我几分钟内无法让它工作： http://blogs.msdn.com/b/pfxteam/archive/2011/11/10/10235834.aspx [ ^ ]



B）

使用工人： http://msdn.microsoft.com/en-us/library/7a2f3ay4(v = vs.90）.aspx [ ^ ]



C）

对于线程，您可以使用这种方法： http://dotnet-snippets.com/snippet/end-thread-after-timeout/656 [ ^ ]，但是你要小心踩踏胎面。 （另请参阅： http://msdn.microsoft.com/en-us/library/5b50fdsz.aspx [ ^ ]） />


无论如何，当你停止这样的执行时，你应该非常小心清理你的资源。

Please note, that this is no brute-force cancellation. It won't "kill" the task, it requires neat finishing. So if you are blocked inside one operation - let's call it atomic in this sense -, this won't help you. (Source: http://www.blackwasp.co.uk/TaskCancellation_2.aspx[^])

You can however not wait in this manner for the task to complete, you could do anything else in your service in the meantime.

An interesting article, but I couldn't get it working in a few minutes: http://blogs.msdn.com/b/pfxteam/archive/2011/11/10/10235834.aspx[^]

B)
Using workers: http://msdn.microsoft.com/en-us/library/7a2f3ay4(v=vs.90).aspx[^]

C)
For threading, you could use this approach: http://dotnet-snippets.com/snippet/end-thread-after-timeout/656[^], however you have top be careful with aborting treads. (see also: http://msdn.microsoft.com/en-us/library/5b50fdsz.aspx[^])

Anyway, you should be very careful with cleaning your resources when you stop such an execution.

试试这个：

Try this:

using System.Diagnostics; // add this line to the top of your code file

Stopwatch sw = new Stopwatch();
sw.Start();
for (int i = 0; i < 10000; i++)
{
    if (sw.Elapsed.TotalMinutes >= 10)
    {
        // some actions before breaking out the loop
        sw.Stop();
        break;
    }
    // other actions here
}
if (sw.IsRunning)
{
    sw.Stop();
}

希望这有帮助。

Hope this helps.

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