Xamarin PCL缺少的System.Timer

Question

我正在使用.Net 4.5.1構建一個針對iOS Android和Windows Phone 8.1的Xamarin跨平臺應用程序。當我嘗試在PCL項目中引用System.Timers時，它不在那裏。我該如何解決？

Answer 1

您可以使用：Device.StartTimer

語法：

public static void StartTimer (TimeSpan interval, Func<bool> callback) 

例子：增量數，每1秒1分鐘

int number = 0; 
Device.StartTimer(TimeSpan.FromSeconds(1),() => { 
    number++; 
    if(number <= 60) 
    { 
     return true; //continue 
    } 
    return false ; //not continue 

}); 

例子：等待5秒鐘運行功能一次

Device.StartTimer(TimeSpan.FromSeconds(5),() => { 
    DoSomething(); 
    return false ; //not continue 
}); 

Answer 2

我前幾天注意到了這一點。儘管該課程在API文檔System.Threading.Timer Class ..Annoying中。

無論如何，我創建了自己的Timer類，使用Task.Delay()：

public class Timer 
{ 

     private int _waitTime; 
     public int WaitTime 
     { 
      get { return _waitTime; } 
      set { _waitTime = value; } 
     } 

     private bool _isRunning; 
     public bool IsRunning 
     { 
      get { return _isRunning; } 
      set { _isRunning = value; } 
     } 

     public event EventHandler Elapsed; 
     protected virtual void OnTimerElapsed() 
     { 
      if (Elapsed != null) 
      { 
       Elapsed(this, new EventArgs()); 
      } 
     } 

     public Timer(int waitTime) 
     { 
      WaitTime = waitTime; 
     } 

     public async Task Start() 
     { 
      int seconds = 0; 
      IsRunning = true; 
      while (IsRunning) 
      { 
       if (seconds != 0 && seconds % WaitTime == 0) 
       { 
        OnTimerElapsed(); 
       } 
       await Task.Delay(1000); 
       seconds++; 
      } 
     } 

     public void Stop() 
     { 
      IsRunning = false; 
     } 
}