DropDownList1實現傳值再DataGuid中

private void Page_Load(object sender, System.EventArgs e)
  {
   if(!Page.IsPostBack)
   {
   
    DataTable dtList=new DataTable();
    dtList=GetQuery(DropDownList1.SelectedIndex);
    this.DataGrid1.DataSource=dtList.DefaultView;
    this.DataGrid1.DataBind();
   }
  }

private void DropDownList1_SelectedIndexChanged(object sender, System.EventArgs e)
  {
   DataTable dtList=new DataTable();
   dtList=GetQuery(DropDownList1.SelectedIndex);
   this.DataGrid1.DataSource=dtList.DefaultView;
   this.DataGrid1.DataBind();
  }

  private DataTable GetQuery(int SelectIndex)
  {
   string strCmdText="";   

   SqlConnection conn =new SqlConnection();
   DataSet ds = new DataSet();
   DataTable dtResult = new DataTable("QueryDateTime");
   ds.Tables.Add("QueryDateTime");
   switch(SelectIndex)
   {
    case 0:
     strCmdText="select staff_name as 姓名,staff_sex as 性別,staff_native as 籍貫,staff_diploma as 學歷,staff_ismarry as 婚否 ,staff_birthday as 出生年月 ,staff_identitycard as 證件號碼,staff_skill as 特長,staff_old_dept as 原單位,staff_old_leavedate as 離職時間,staff_rapport as 關係,introducer_dept as 介紹人部門,introducer_name as 介紹人姓名,introducer_indate as 入廠時間  from Staff_Register ";
     conn=DBC.CreateDB();
     break;
     case 1:
       strCmdText="select staff_name as 姓名,staff_sex as 性別,staff_native as 籍貫,staff_diploma as 學歷,staff_ismarry as 婚否 ,staff_birthday as 出生年月 ,staff_identitycard as 證件號碼,staff_skill as 特長,staff_old_dept as 原單位,staff_old_leavedate as 離職時間,staff_rapport as 關係,introducer_dept as 介紹人部門,introducer_name as 介紹人姓名,introducer_indate as 入廠時間 from Staff_Register where staff_identitycard not in (select staff_identitycard from Staff_Register where staff_identitycard in (select id_no from [it-srv-db1].fc_person_data.dbo.trans_staff where status>0)) and  staff_identitycard not in (select staff_identitycard from  [it-srv-db1].fc_person_data.dbo.trans_staff Where out_date Is Not Null  And out_date<>'' Or datediff(dd,in_date,getdate())<30) and staff_identitycard not in (select staff_identitycard from Staff_Register A, (select  department_no,staff_name,introducer_remark,in_date from [it-srv-db1].fc_person_data.dbo.trans_staff where datediff(dd,in_date,getdate())<30  ) B Where A.introducer_name=B.staff_name) and staff_identitycard not in (select staff_identitycard from Staff_Register where datediff(yy,staff_birthday,getdate())<18 Or datediff(yy,staff_birthday,getdate())>35)";
          conn=DBC.CreateDB();
     break;
     case 2:
          strCmdText="select staff_name as 姓名,staff_identitycard as 身份證號碼 from Staff_Register where staff_identitycard in (select id_no from [it-srv-db1].fc_person_data.dbo.trans_staff where status>0) ";
          conn=DBC.CreateDB();
     break;
    case 3:
     strCmdText="select A.staff_name as 姓名,staff_sex as 性別,staff_native as 籍貫,B.out_date as 出廠日期  from Staff_Register A Inner Join [it-srv-db1].fc_person_data.dbo.trans_staff B On A.staff_identitycard=B.id_no And  (B.id_no  is null Or  datediff(dd,B.out_date,getdate())<30)";
     conn=DBC.CreateDB();
     break;
     case 4:
         strCmdText="select A.staff_name as 姓名 ,B.staff_name as 介紹人姓名 ,B.department_no as 介紹人部門,B.introducer_remark as 介紹人關係,B.in_date as 入敞時間 from Staff_Register A, (select  department_no,staff_name,introducer_remark,in_date  from [it-srv-db1].fc_person_data.dbo.trans_staff where datediff(dd,in_date,getdate())<30  ) B Where A.introducer_name=B.staff_name ";
            conn=DBC.CreateDB();
     break;
    case 5:
     strCmdText="select staff_name as 姓名,staff_birthday as 出生年月 from Staff_Register where datediff(yy,staff_birthday,getdate())<18 Or datediff(yy,staff_birthday,getdate())>35 order by staff_birthday desc";
     conn=DBC.CreateDB();
     break;
   } 
  

   SqlDataAdapter sqlDA = new SqlDataAdapter(strCmdText,conn);   
   sqlDA.Fill(ds,"QueryDateTime");     
   dtResult=ds.Tables[0];
   return dtResult;
  }

  private void DataGrid1_PageIndexChanged(object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
  {
   this.DataGrid1.CurrentPageIndex=e.NewPageIndex;
  }