c# richtextbox更新大量数据不卡死的实现方式

        maxDisplayline = 1 * 1000; // 1000行
       StringBuilder sb = new StringBuilder();
        Stopwatch swGlobal = new Stopwatch();
        string[] sblineslist = in_str.Split(new char[] { '\n' }); // instr 为输入字符串，可以是文件读入的
        // static readonly object lockSb = new object();

        richTextBoxDisplay.Focus();
        sb.Clear();
        Thread.Sleep(1);

        
        swGlobal.Reset(); swGlobal.Start();

        Thread t = new Thread((ThreadStart)delegate
          {
              try
              {
                  for (int i = 0; i < sblineslist.Length; i++)
                  {
                      if (stopSign)
                      {
                          return;
                      }

					// lock(lockSb)
                      sb.Append(sblineslist[i] + "\n");

                      if (i > 0 && i % maxDisplayline == 0)
                      {
                          this.Invoke((EventHandler)delegate { labelStatus.Text = "状态: " + count + "/" + manualSyncFilesFullname.Count + " " + runsecond + "s -> " + (i + 1) 
                              + " Act/Rest: " + swGlobal.ElapsedMilliseconds/1000 + "/" + (int)(1.0 * swGlobal.ElapsedMilliseconds * (sblineslist.Length - (i+1)) /(i+1) /1000) + "s";
                              labelStatus.Update(); });

                          if (sb.Length > 0)
                          {
          						// lock(lockSb)
                              this.richTextBoxDisplay.Text = this.richTextBoxDisplay.Text + sb.ToString();
                              sb.Clear();
                          }

                          maxDisplayline = maxDisplayline * ((int)Math.Sqrt(i/ maxDisplayline));
                      }
                  }

                  if (sb.Length > 0)
                  {
   						// lock(lockSb)
                      this.richTextBoxDisplay.Text = this.richTextBoxDisplay.Text + sb.ToString();
                      sb.Clear();
                  }
                  this.Invoke((EventHandler)delegate { labelStatus.Text = "状态: " + count + "/" + manualSyncFilesFullname.Count + " " + runsecond + "s -> " + sblineslist.Length.ToString()
                      +" Act: " + swGlobal.ElapsedMilliseconds / 1000 + "s";
                      labelStatus.Update(); });
              }
              catch (Exception ex)
              {
                  try
                  {
                      stopSign = true;
                      this.Invoke((EventHandler)delegate { labelStatus.Text = "异常错误: " + ex.Message; labelStatus.Update(); });
                  }
                  catch { }
              }
        });

        t.IsBackground = true;
        t.Start();
        Thread.Sleep(33);

        while (!stopSign && t != null && t.IsAlive)
        {
            Application.DoEvents();
            Thread.Sleep(3);
        }