c# BackgroundWorker的基本用法

转自 http://blog.csdn.net/coolwxb/article/details/7388499

这也是今天讨论的话题。取消是默认就支持的，而暂停则默认不支持。但通过ManualResetEvent可以对其进行干预。

using System;  using System.Collections.Generic;  using System.ComponentModel;  using System.Data;  using System.Drawing;  using System.Linq;  using System.Text;  using System.Windows.Forms;  using System.Threading;namespace BackgroundWorkderPauseSample  {      public partial class MainForm : Form      {          BackgroundWorker worker = null;          public MainForm()          {              InitializeComponent();              Load += new EventHandler(Form1_Load);          }          void Form1_Load(object sender, EventArgs e)          {              worker = new BackgroundWorker();              worker.WorkerReportsProgress = true;              worker.WorkerSupportsCancellation = true;              worker.DoWork += new DoWorkEventHandler(worker_DoWork);              worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);              worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);          }          void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)          {              progressBar1.Value = e.ProgressPercentage;          }          void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)          {              if (e.Cancelled)                  MessageBox.Show("用户取消了操作");              else              {                  MessageBox.Show("正常完成了操作");              }          }          void worker_DoWork(object sender, DoWorkEventArgs e)          {              for (int i = 0; i < 100; i++)              {                  if (worker.CancellationPending)//如果用户申请取消                  {                      for (int k = i; k >= 0; k--)                      {                          Thread.Sleep(10);                          worker.ReportProgress(k);//模拟一个回滚的效果                      }                      e.Cancel = true;                      return;                  }                  //如果ManualResetEvent的初始化为终止状态（true），那么该方法将一直工作，直到收到Reset信号。然后，直到收到Set信号，就继续工作。                  manualReset.WaitOne();                //反之亦然                  Thread.Sleep(500);                  worker.ReportProgress(i+1);              }          }          private void btStart_Click(object sender, EventArgs e)          {              worker.RunWorkerAsync();          }          private void btCancel_Click(object sender, EventArgs e)          {              worker.CancelAsync();          }          private ManualResetEvent manualReset = new ManualResetEvent(true);          private void btPause_Click(object sender, EventArgs e)          {              if (btPause.Text == "暂停")              {                  manualReset.Reset();//暂停当前线程的工作，发信号给waitOne方法，阻塞                  btPause.Text = "继续";              }              else              {                  manualReset.Set();//继续某个线程的工作                  btPause.Text = "暂停";              }          }      }  }

这个程序运行的效果大致如下
一。正常状态

二。暂停状态

三。恢复状态

作为演示，代码比较简单，没有对worker的一些状态进行判断以及按钮相应的设置。仅供参考