Question

有一个在任务中执行的过程。我不希望其中一个同时执行。

这是检查任务是否已在运行的正确方法吗？

private Task task;

public void StartTask()
{
    if (task != null && (task.Status == TaskStatus.Running || task.Status == TaskStatus.WaitingToRun || task.Status == TaskStatus.WaitingForActivation))
    {
        Logger.Log("Task has attempted to start while already running");
    }
    else
    {
        Logger.Log("Task has began");

        task = Task.Factory.StartNew(() =>
        {
            // Stuff                
        });
    }
}

Answer 1

根据Jon Skeet的建议，Task.IsCompleted是更好的选择。

根据MSDN：

当任务处于三者之一时，
IsCompleted将返回true 最终状态：RanToCompletion，Faulted或Canceled。

但它似乎也在TaskStatus.WaitingForActivation状态下返回true。

Answer 2

private Task task;

public void StartTask()
{
    if ((task != null) && (task.IsCompleted == false ||
                           task.Status == TaskStatus.Running ||
                           task.Status == TaskStatus.WaitingToRun ||
                           task.Status == TaskStatus.WaitingForActivation))
    {
        Logger.Log("Task is already running");
    }
    else
    {
        task = Task.Factory.StartNew(() =>
        {
            Logger.Log("Task has been started");
            // Do other things here               
        });
    }
}

Answer 3

您可以查看：

if ((taskX == null) || (taskX.IsCompleted))
{
   // start Task
   taskX.Start();
   //or
   taskX = task.Factory.StartNew(() =>
   {
      //??
   }
}

在开始新任务之前检查任务是否已在运行

3 个答案: