C# 在开始新任务之前检查任务是否已经在运行
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Check if task is already running before starting new
提问by Dave New
There is a process which is executed in a task. I do not want more than one of these to execute simultaneously.
有一个在任务中执行的进程。我不希望其中多个同时执行。
Is this the correct way to check to see if a task is already running?
这是检查任务是否已经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
});
}
}
采纳答案by Dave New
As suggested by Jon Skeet, the Task.IsCompletedis the better option.
正如 Jon Skeet 所建议的，这Task.IsCompleted是更好的选择。
According to MSDN:
根据MSDN：
IsCompletedwill return true when the task is in one of the three final states:RanToCompletion,Faulted, orCanceled.
IsCompleted当任务是在三个最终状态之一将返回true：RanToCompletion，Faulted或Canceled。
But it appears to return true in the TaskStatus.WaitingForActivationstate too.
但它似乎也返回 trueTaskStatus.WaitingForActivation状态。
回答by Sayka
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
});
}
}
回答by guest123
You can check it with:
您可以通过以下方式检查：
if ((taskX == null) || (taskX.IsCompleted))
{
// start Task
taskX.Start();
//or
taskX = task.Factory.StartNew(() =>
{
//??
}
}
回答by Mohammad Kohanrooz
Even easier:
更简单：
if (task?.IsCompleted ?? true)
task = TaskFunction();
