AspNetPager查询分页问题（点击页码，不再是查询后的数据集）viewstate解决

public  string  SQL = "select * from Memorandum" ;
      protected  void  Page_Load( object  sender, EventArgs e)
      {
          if  (!IsPostBack)
          {
              ViewState[ "SQL" ] = SQL;
              BindData();
          }
          if  (Request.QueryString[ "MId" ] != null )
          {
              Delete( int .Parse(Request.QueryString[ "MId" ].ToString()));
          }
      }

      protected  void  AspNetPager1_PageChanged( object  sender, EventArgs e)
      {
          BindData();
      }

      void  BindData()
      {
          PagedDataSource pds = new  PagedDataSource();
          IList<MemorandumInfo> Infos = new  DAL.Memorandum().GetAllMemorandumsBySQL(ViewState[ "SQL" ].ToString());

          pds.DataSource = Infos;
          pds.AllowPaging = true ;
          pds.PageSize = 10; //取控件的分页大小
          pds.CurrentPageIndex = this .AspNetPager1.CurrentPageIndex - 1; //显示当前页
          //设置控件
          this .AspNetPager1.RecordCount = Infos.Count; //记录总数
          this .AspNetPager1.PageSize = 10;
          Repeater1.DataSource = pds;
          Repeater1.DataBind();
      }
      void  Delete( int  MId)
      {
          new  Memorandum().DeleteMemorandum(MId);
          Response.Write( "<script>alert('成功删除该条备忘信息');location='?';</script>" );
      }
      /// <summary>
      /// 查询
      /// </summary>
      /// <param name="sender"></param>
      /// <param name="e"></param>

      protected  void  Button1_Click( object  sender, EventArgs e)
      {
          if  (DropDownList1.SelectedValue == "0" )
          {
              ViewState[ "SQL" ] = "select * from Memorandum" ;
              BindData();
          }
          else
          {
              ViewState[ "SQL" ] = "SELECT   MId, MemoTitle, MemoContent, MemoStartTime, MemoEndTime FROM  Memorandum WHERE (MemoEndTime - NOW() <=7)" ;
              BindData();
          }
      }
  }

ViewState 用来跟踪和保存控件的状态信息。否则这些信息可能会丢失，原因可能是这些值不随着 form 回发，或者根本就不在 page 的 html 中。
ViewState 中保存着代码中改变的控件属性，通过代码绑定到控件的任何数据，以及由用户操作触发，回发的任何更改。
ViewState 还提供了一个状态包(StateBag), 这是一个特殊的集合或字典(collection or dictionary), 可以用来保存，通过一个 key 来恢复任意的对象或者值。

赋值：ViewState[key] = value;

取值：value = ViewState[key];