System.Diagnostics.Process process;
private void btnRAR_Click(object sender, EventArgs e)
{
 if (System.IO.File.Exists("Rar.exe"))
 {
  try
  {
   process = new System.Diagnostics.Process();
   process.StartInfo.FileName = "Rar.exe";
   process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Minimized;
   process.EnableRaisingEvents = true;
   //m<0..5>  设置压缩级别(0-存储...3-默认...5-最大)
   //rar a -m5 -ag[yyyy年mm月dd日_hh点mm分-ss] MyLuoLuo
   process.StartInfo.Arguments = string.Format(@"a -m{0} -ag[yyyy年mm月dd日_hh点mm分-ss] {1}\\MyLuoLuo.rar {2}", this.SaveRank.ToString(),this.FileName,this.RarPath); //@"a -m5 -ag[yyyy年mm月dd日_hh点mm分-ss] MyLuoLuo.rar D:\Txt";
   process.Exited += new EventHandler(RarStop);
   process.Start();
  }
  catch (Exception ex)
  {
   MessageBox.ShowError("发生错误!错误信息:\n" + ex.Message);
  }
 }
}

private void RarStop(object sender, System.EventArgs e)
{
 switch (process.ExitCode)
 {
  case 0:
   MessageBox.ShowInformation("压缩成功！");
   break;
  case 1:
   MessageBox.ShowInformation("有错误但没有发生致命错误！");
   break;
  case 2:
   MessageBox.ShowError("发生一个致命错误！");
   break;
  case 3:
   MessageBox.ShowError("解压缩时发生一个 CRC 错误！");
   break;
  case 4:
   MessageBox.ShowError("试图修改先前使用 'k' 命令锁定的压缩文件！");
   break;
  case 5:
   MessageBox.ShowError("写入磁盘错误！");
   break;
  case 6:
   MessageBox.ShowError("打开文件错误！");
   break;
  case 7:
   MessageBox.ShowError("命令行选项错误！");
   break;
  case 8:
   MessageBox.ShowError("没有足够的内存进行操作！");
   break;
  case 9:
   MessageBox.ShowError("创建文件错误！");
   break;
  case 255:
   MessageBox.ShowError("用户中断操作");
   break;
  default:
   MessageBox.ShowError("未知错误！");
   break;
 }
}