System.NullReferenceException:  未将对象引用设置到对象的实例。
      在  LYWebsite2.LiYongNet.website.Article.Page_Load(Object  sender,  EventArgs  e)
      在  System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object  sender,  EventArgs  e)
      在  System.Web.UI.Control.OnLoad(EventArgs  e)
      在  System.Web.UI.Control.LoadRecursive()
      在  System.Web.UI.Page.ProcessRequestMain(Boolean  includeStagesBeforeAsyncPoint,  Boolean  includeStagesAfterAsyncPoint)