Asp.Net程序目录下文件夹或文件操作导致Session失效

<system.web>
  <sessionState mode="StateServer" stateConnectionString="tcpip=127.0.0.1:42424" sqlConnectionString="data 
  source=127.0.0.1;Trusted_Connection=yes" cookieless="false" timeout="40"/>
</system.web>

void Application_Start(object sender, EventArgs e)
  {
    // 在应用程序启动时运行的代码
    try
    {
      //启动ASP.NET 状态服务
      string g_serviceName = "asp_state";
      System.ServiceProcess.ServiceController[] serviceControllers = 
        System.ServiceProcess.ServiceController.GetServices();
      foreach (System.ServiceProcess.ServiceController service in serviceControllers)
      {
        if (service.ServiceName == g_serviceName)
        {
          if (service != null && service.Status != System.ServiceProcess.ServiceControllerStatus.Running)
          {
            service.Start();
　　　　　　　　　　　　　　 SimpleLogHelper.WriteError(g_serviceName + "服务已开启");
          }
          else
          {
            if (service == null)
            {
              SimpleLogHelper.WriteError(g_serviceName + "服务未安装");
            }
            else
            {
              SimpleLogHelper.WriteError(g_serviceName + "服务正在运行...");
            }
          }
          break;
        }
      }
    }
    catch (Exception ex)
    {
      SimpleLogHelper.WriteError(ex.ToString());
    }
  }