asp.net利用多线程执行长时间的任务，客户端显示出任务的执行进度的示例

namespace csdn
{
 /// <summary>
 /// webform54 的摘要说明。
 /// </summary>
 public class webform54 : system.web.ui.page
 {
  protected system.web.ui.htmlcontrols.htmlgenericcontrol div_load;
  protected system.web.ui.webcontrols.button btn_startwork;
  protected system.web.ui.webcontrols.label lab_state;
  protected system.web.ui.webcontrols.label lab_jg;
  protected work w;

  private void page_load(object sender, system.eventargs e)
  {
   // 在此处放置用户代码以初始化页面
   if(session["work"]==null)
   {
    w=new work();
    session["work"]=w;
   }
   else
   {
    w=(work)session["work"];
   }
   switch(w.state)
   {
    case 0:
    {
     this.div_load.visible=false;
     break;
    }
    case 1:
    {
     this.lab_state.text=""+((timespan)(datetime.now-w.starttime)).totalseconds.tostring("0.00")+" 秒过去了，完成百分比："+w.percent+" ％";
     this.btn_startwork.enabled=false;
     page.registerstartupscript("","<script>window.settimeout('location.href=location.href',1000);</script>");
     this.lab_jg.text="";
     break;
    }
    case 2:
    {
     this.lab_jg.text="任务结束,并且成功执行所有操作,用时 "+((timespan)(w.finishtime-w.starttime)).totalseconds+" 秒";
     this.btn_startwork.enabled=true;
     this.div_load.visible=false;
     break;
    }
    case 3:
    {
     this.lab_jg.text="任务结束,在"+((timespan)(w.errortime-w.starttime)).totalseconds+"秒的时候发生错误导致任务失败'";
     this.btn_startwork.enabled=true;
     this.div_load.visible=false;
     break;
    }
   }
  }

  #region web 窗体设计器生成的代码
  override protected void oninit(eventargs e)
  {
   //
   // codegen: 该调用是 asp.net web 窗体设计器所必需的。
   //
   initializecomponent();
   base.oninit(e);
  }
  
  /// <summary>
  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  /// </summary>
  private void initializecomponent()
  {   
   this.btn_startwork.click += new system.eventhandler(this.btn_startwork_click);
   this.load += new system.eventhandler(this.page_load);

  }
  #endregion

  private void btn_startwork_click(object sender, system.eventargs e)
  {
   if(w.state!=1)
   {
    this.btn_startwork.enabled=false;
    this.div_load.visible=true;
    w.runwork();
    page.registerstartupscript("","<script>location.href=location.href;</script>");
            
   }
  }
 }

 public class work
 {
  public int state=0;//0-没有开始,1-正在运行,2-成功结束,3-失败结束
  public int percent=0;//完成百分比
  public datetime starttime;
  public datetime finishtime;
  public datetime errortime;

  public void runwork()
  {
   lock(this)
   {
    if(state!=1)
    {
     state=1;
     starttime=datetime.now;
     system.threading.thread thread=new system.threading.thread(new system.threading.threadstart(dowork));
     thread.start();                        
    }
   }
  }

  private void dowork()
  {
   try
   {
    sqlconnection conn=new sqlconnection(system.configuration.configurationsettings.appsettings["conn"]);
    sqlcommand cmd=new sqlcommand("insert into test (test)values('test')",conn);
    conn.open();
    for(int p=0;p<100;p++)
    {
     for(int i=0;i<10;i++)
     {
      cmd.executenonquery();
     }
     percent=p;//这里就是定义百分比，你估计这个操作费多少时间定义多少百分比
    }
    conn.close();
    //以上代码执行一个比较消耗时间的数据库操作
    state=2;
   }
   catch
   {
    errortime=datetime.now;
    percent=0;
    state=3;
   }
   finally
   {
    finishtime=datetime.now;
    percent=0;
   }
  }
 }
}