c# timer.elapsed？

Question

我已经包含了System.Timers包，但是当我键入以下内容时：

Timer.Elapsed; //its not working, the property elapsed is just not there.

我记得它就在VB.NET里，为什么这个不起作用呢？

Answer 1

这不是一处房产。It's an event。

因此，您必须提供一个事件处理程序，该处理程序将在每次计时器滴答作响时执行。如下所示：

public void CreateTimer() 
{
    var timer = new System.Timers.Timer(1000); // fire every 1 second
    timer.Elapsed += HandleTimerElapsed;
}

public void HandleTimerElapsed(object sender, ElapsedEventArgs e)
{
    // do whatever it is that you need to do on a timer
}

Answer 2

微软的例子。http://msdn.microsoft.com/en-us/library/system.timers.timer.elapsed.aspx

Elapsed是一个事件，因此需要一个eventhandler。

using System;
using System.Timers;

public class Timer1
{
private static System.Timers.Timer aTimer;

public static void Main()
{       
    // Create a timer with a ten second interval.
    aTimer = new System.Timers.Timer(10000);

    // Hook up the Elapsed event for the timer.
    aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);

    // Set the Interval to 2 seconds (2000 milliseconds).
    aTimer.Interval = 2000;
    aTimer.Enabled = true;

    Console.WriteLine("Press the Enter key to exit the program.");
    Console.ReadLine();       
}

// Specify what you want to happen when the Elapsed event is  
// raised. 
private static void OnTimedEvent(object source, ElapsedEventArgs e)
{
    Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime);
}
}

/* This code example produces output similar to the following:

Press the Enter key to exit the program.
The Elapsed event was raised at 5/20/2007 8:42:27 PM
The Elapsed event was raised at 5/20/2007 8:42:29 PM
The Elapsed event was raised at 5/20/2007 8:42:31 PM
...
 */

Answer 3

前面的答案都是正确的，但是随着.net 6/ VS2022的发布，空性是个大问题，所有上面的答案都会抛出编译器警告CS8622。

解决这个问题的方法是在回调函数的参数中将源对象标记为可空，如下所示：

...
    timer.Elapsed += TimerElapsedHandler;
...

public void TimerElapsedHandler(object? source, ElapsedEventArgs e)
{
    //Your Handling Code Here
}