天天向上

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Threading;

Task taskTimer;                     // timer任務實體

delegate void showTimeHandler();    // 顯示時間委派函式

ManualResetEvent pauseSignal;       // 控制任務 暫停或繼續

int cnt = 0;                        // 計數器

// 啟動非同步任務

   private async void button5_Click(object sender, EventArgs e)

   {

       pauseSignal = new ManualResetEvent(true);   

       taskTimer = new Task(timerCallback);

       taskTimer.Start();

       await taskTimer;

   }

private void timerCallback()

{

    while (true)

    {

        pauseSignal.WaitOne();

        showTime();                           // 顯示目前時間

        cnt++;

        SpinWait.SpinUntil(() => false, 500); // 0.5更新一次

    }

}

// 顯示時間副程式

       private void showTime()

       {

           if (this.label1.InvokeRequired)

           {

               showTimeHandler handler = new showTimeHandler(showTime);

               this.Invoke(handler);

           }

           else

           {

               label1.Text = DateTime.Now.ToLongTimeString();

               label2.Text = cnt.ToString();

           }

       }

// 暫停任務

    private void button6_Click(object sender, EventArgs e)

    {

        pauseSignal.Reset();

    }

private void button7_Click(object sender, EventArgs e)

{

    pauseSignal.Set();

}