使用计时器将操作延迟几秒钟

Question

I am trying to delay my method by using a timer:

private System.Timers.Timer _delayTimer;

    private void delay()
    {
          _delayTimer = new System.Timers.Timer();
          _delayTimer.Interval = 5000;
          //_delayTimer.Enabled = true;
          _delayTimer.Elapsed += _delayTimer_Elapsed;
          _delayTimer.Start();
          someMethod();
        }
    }

    private void _delayTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        // delay for 5 seconds
    }

When i am get into delay() method i want to start the timer, than i want the 5 seconds delay and only after that i want to execute someMethod() and currently this not happen, after execute delay() the someMethod() executed without 5 seconds delay

Answer 1

Your current code sets up the timer and then immediately executes someMethod . Instead of this, you need to put the actual method call inside your Elapsed handler:

private void delay()
{
      _delayTimer = new System.Timers.Timer();
      _delayTimer.Interval = 5000;
      //_delayTimer.Enabled = true;
      _delayTimer.Elapsed += _delayTimer_Elapsed;
      _delayTimer.Start();
    }
}

private void _delayTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
      someMethod();
}

And if there's nothing else you intend to do you can simply write this inline:

_delayTimer = new System.Timers.Timer();
_delayTimer.Interval = 5000;
_delayTimer.Elapsed += (o, e) => someMethod();
_delayTimer.Start();

Answer 2

If you're in .Net4.5(or using BCL.Async pack) you can use Task.Delay

private async void delay()
{
    await Task.Delay(5000);
    someMethod();
}

If you're under .Net4.5

Try the below code. I'll suggest you to use System.Threading.Timer

var timer = new System.Threading.Timer(x => someMethod(), null, 5000, System.Threading.Timeout.Infinite);\

Don't forget when you use Threading.Timer someMethod will be invoked in ThreadPool thread, If you're accessing UI you need to marshal the call to UI thread.

Answer 3

If you want the current thread to pause for five seconds, then call Thread.Sleep . For example:

Thread.Sleep(TimeSpan.FromSeconds(5));
DoSomething();

Use a timer if you want something to happen five seconds from now, while you're doing something else. When the timer elapses, the action will be executed on a thread pool thread.

Also, if you only want the timer to execute one time (rather than once every five seconds), be sure to set AutoReset to false .

Answer 4

You need to call someMethod in the timer's Elapsed handler:

private void delay()
{
      _delayTimer = new System.Timers.Timer();
      _delayTimer.Interval = 5000;
      _delayTimer.AutoReset = false; //so that it only calls the method once
      _delayTimer.Elapsed += (s,args) => someMethod();
      _delayTimer.Start();
}

You could also use Task.Delay instead:

private void delay()
{
    Task.Delay(5000)
    .ContinueWith(t => someMethod());
}

Answer 5

System.Threading.Tasks.Task.Factory.StartNew(() =>
            {
                System.Threading.Thread.Sleep(5000);
                /*
                 * Here Yopur code to do some method :D
                 * */
            });