c# 后台程序

C# 中的backgroundworker，是我个人认为最具有吸引力的windows标准控件之一，他允许程序在后台运行一个独立的线程，而不影响前台主窗口。这种进程控制在操作数据库或通讯时非常实用，因为后台线程在工作时并不影响前台的任何操作。如果不使用backgroundworker而简单的应用单一线程操作，则通讯时很有可能会造成主窗口假死，知道通讯结束后才会恢复。下面简单介绍了backgroundworker的用法：

#region ( worker 1 )
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            e.Result = NormalTest(backgroundWorker1, e);
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            ProgressBar1.Value = e.ProgressPercentage;
            Label1.Text = ProgressBar1.Value.ToString() + "%";
            Label1.BackColor = Color.Orange;
            Label1.ForeColor = Color.White;
        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (position == 0)
            {
                Label1.BackColor = Color.Green;

                Button_Run1.Enabled = true;
                Button_Pause1.Enabled = false;
                Button_Resume1.Enabled = false;
                Button_Stop1.Enabled = false;

            }
        }
 #endregion

        private void Button_Run1_Click(object sender, EventArgs e)
        {
            position = 0;
     
            backgroundWorker1.RunWorkerAsync();
   
            Button_Run1.Enabled = false;
            Button_Pause1.Enabled = true;
            Button_Resume1.Enabled = false;
            Button_Stop1.Enabled = true;
        }


        private void Button_Pause1_Click(object sender, EventArgs e)
        {
         
            backgroundWorker1.CancelAsync();
   

            Button_Run1.Enabled = false;
            Button_Pause1.Enabled = true;
            Button_Resume1.Enabled = true;
            Button_Stop1.Enabled = true;
        }

        private void Button_Resume1_Click(object sender, EventArgs e)
        {
           
             backgroundWorker1.RunWorkerAsync();
       

            Button_Run1.Enabled = false;
            Button_Pause1.Enabled = true;
            Button_Resume1.Enabled = false;
            Button_Stop1.Enabled = true;
        }
        private void Button_Stop1_Click(object sender, EventArgs e)
        {
            position = 0;
            
            backgroundWorker1.CancelAsync();

            Button_Run1.Enabled = false;
            Button_Pause1.Enabled = true;
            Button_Resume1.Enabled = false;
            Button_Stop1.Enabled = true;
        }

        private int NormalTest(BackgroundWorker work, DoWorkEventArgs e)
        {
            #region [ Pause Testing ]
            if (work.CancellationPending)
            {
                return position;
            }
            #endregion

            for (int i = position; i < nop; i++)
            {
                #region [ Pause Testing ]
                if (work.CancellationPending)
                {
                    return position;
                }
                #endregion
               
                ..

                position = i;
                work.ReportProgress((position + 1) * 100 / nop);
            }

            position = 0;

            return position;
         }

有一点需要注意，backgroundworker不能直接操作前台windows窗口中的控件，否则会引起线程的不安全。