简单使用BackgroundWorker创建多个线程的教程(4)

上面代码中的停止不是能立即停止，这个就和开车一样，开的越快，刹车的后拖行的距离越长，同理，开启的线程的越多，完全暂停需要的时间越长，不知我说的是否正确。另外我也想问一下是否能真正的全部线程停止，点停止后全部线程立即停止。

下面我们继续加入暂停和继续的功能，一样的道理，我们使用List<ManualResetEvent>。

复制代码 代码如下:

List<BackgroundWorker> bws = new List<BackgroundWorker>();
 List<ManualResetEvent> mrs = new List<ManualResetEvent>(); 
 int t = 10;

 private void button1_Click(object sender, EventArgs e)
 {
     for (int i = 0; i < t; i++)
     {
         BackgroundWorker bw = new BackgroundWorker();
         bw.DoWork += new DoWorkEventHandler(bw_DoWork);
         bw.WorkerSupportsCancellation = true;
         bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
         bws.Add(bw);

         bw.RunWorkerAsync(i);

         mrs.Add(new ManualResetEvent(true));
     }
 }

 private void button2_Click(object sender, EventArgs e)
 {
     for (int i = 0; i < t; i++)
     {
         bws[i].CancelAsync();
     }
 }

 private void button3_Click(object sender, EventArgs e)
 {
     Button b = (Button)sender;  
     if (b.Text == "暂停")  
     {  
         for (int i = 0; i < mrs.Count; i++)  
         {  
             mrs[i].Reset();  
         }  
         b.Text = "继续";  
     }  
     else 
     {  
         for (int i = 0; i < mrs.Count; i++)  
         {  
             mrs[i].Set();  
         }  
         b.Text = "暂停";  
     }  
 }

 void bw_DoWork(object sender, DoWorkEventArgs e)
 {
     int j = Convert.ToInt32(e.Argument);
     for (int i = j; i < 1000; i = i + t)
     {
         if (((BackgroundWorker)sender).CancellationPending) 
         {
             e.Cancel = true;
             return;
         }

         string item = String.Format("线程{0}正在操作数据{1}", j + 1, i);

         this.Invoke((MethodInvoker)delegate
         {
             this.richTextBox1.Text += item + Environment.NewLine;
         });

         Thread.Sleep(200);
         mrs[j].WaitOne(); 
     }
 }

 void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
 {
     bws.Remove(sender as BackgroundWorker);
     if (bws.Count == 0)
     {
         if (e.Cancelled)
         {
             this.richTextBox1.Text += "线程已经停止";
         }
         else
         {
             this.richTextBox1.Text += "线程已经完成";
         }
     }
 }