C#에서 BackgroundWorker 사용법에 대한 자세한 설명(그림)

private BackgroundWorker _demoBGWorker = new BackgroundWorker();
_demoBGWorker.DoWork += BGWorker_DoWork;
_demoBGWorker.RunWorkerAsync();
private void BGWorker_DoWork(object sender, DoWorkEventArgs e)
{
  //在这里执行耗时的运算。
  int sum = 0;
  for (int i = 0; i <= 100; i++)
  {
    sum += i;
  }
}

//别忘了设置滚动条。
this.progressBarSum.Maximum = 100;
_demoBGWorker.RunWorkerAsync(100);
//下面是更新后的 BGWorker_DoWork 方法：
private void BGWorker_DoWork(object sender, DoWorkEventArgs e)
{
  //在这里执行耗时的运算。
  int endNumber = 0;
  if(e.Argument != null)
  {
    endNumber = (int)e.Argument;
  }
  int sum = 0;
  for (int i = 0; i <= endNumber; i++)
  {
    sum += i;
  }
}

_demoBGWorker.WorkerReportsProgress = true;
_demoBGWorker.ProgressChanged += BGWorker_ProgressChanged;

private void BGWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
  //修改进度条的显示。
  this.progressBarSum.Value = e.ProgressPercentage;

  //如果有更多的信息需要传递，可以使用 e.UserState 传递一个自定义的类型。
  //这是一个 object 类型的对象，您可以通过它传递任何类型。
  //我们仅把当前 sum 的值通过 e.UserState 传回，并通过显示在窗口上。
  string message = e.UserState.ToString();
  this.labelSum.Text = message;
}

private void BGWorker_DoWork(object sender, DoWorkEventArgs e)
{
  BackgroundWorker bgWorker = sender as BackgroundWorker;
  int endNumber = 0;
  if(e.Argument != null)
  {
    endNumber = (int)e.Argument;
  }

  int sum = 0;
  for (int i = 0; i <= endNumber; i++)
  {
    sum += i;
    
    string message = "Current sum is: " + sum.ToString();
    //ReportProgress 方法把信息传递给 ProcessChanged 事件处理函数。
    //第一个参数类型为 int，表示执行进度。
    //如果有更多的信息需要传递，可以使用 ReportProgress 的第二个参数。
    //这里我们给第二个参数传进去一条消息。
    bgWorker.ReportProgress(i, message);
    Thread.Sleep(600);
  }
}

_demoBGWorker.WorkerSupportsCancellation = true;

 bgWorker.ReportProgress(i, message);
Thread.Sleep(600);

//在操作的过程中需要检查用户是否取消了当前的操作。
if (bgWorker.CancellationPending == true)
{
  e.Cancel = true;
  break;
}

_demoBGWorker.CancelAsync();

_demoBGWorker.RunWorkerCompleted += BGWorker_RunWorkerCompleted;
private void BGWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
  //如果用户取消了当前操作就关闭窗口。
  if (e.Cancelled)
  {
    this.Close();
  }

  //计算已经结束，需要禁用取消按钮。
  this.btnCancel.Enabled = false;

  //计算过程中的异常会被抓住，在这里可以进行处理。
  if (e.Error != null)
  {
    Type errorType = e.Error.GetType();
    switch (errorType.Name)
    {
      case "ArgumentNullException":
      case "MyException":
        //do something.
        break;
      default:
        //do something.
        break;
    }
  }

  //计算结果信息：e.Result
  //use it do something.
}