急求救一个Datagrid分页有关问题速来.

急求救一个Datagrid分页问题大虾速来.....
datagrid自定义分页功能.点击第二页正常.编辑的时候就跑到第一页了.不知道怎么解决..
代码:
Dim   cn   As   New   SqlConnection( "server=.;database=testDb;uid=sa ")
Dim   rowCount   As   Integer
Dim   startIndex   As   Integer
  Private   Sub   Page_Load(ByVal   sender   As   System.Object,   ByVal   e   As   System.EventArgs)   Handles   MyBase.Load
                If   Not   IsPostBack   Then
                        DataGridDataBind()
                End   If
        End   Sub
  Private   Sub   DataGridDataBind()
                Try
                   
                        Dim   da   As   New   SqlDataAdapter( "select   bookName,UnitsInStock,UnitPrice,bookID,book.publishID,bookImg,book.CategoryID,bookBrief,auther,CategoryName,publishName   from   book,Categories,publish   where   book.CategoryID=Categories.CategoryID   and   book.publishID=publish.publishID ",   cn)
                        Dim   ds   As   New   DataSet
                        cn.Open()
                        da.Fill(ds,   startIndex,   DataGrid1.PageSize,   "book ")   '指定索引开始取记录
                        da.Fill(ds,   "AllDataTable ")
                        DataGrid1.VirtualItemCount   =   ds.Tables( "AllDataTable ").Rows.Count   '   获取自定义实际页数
                        DataGrid1.DataSource   =   ds.Tables( "book ")
                        rowCount   =   ds.Tables( "book ").Rows.Count
                        DataGrid1.DataBind()
                Catch   ex   As   Exception
                        Response.Write(ex.Message)
                Finally
                        cn.Close()
                End   Try
        End   Sub
  Private   Sub   DataGrid1_EditCommand(ByVal   source   As   Object,   ByVal   e   As   System.Web.UI.WebControls.DataGridCommandEventArgs)   Handles   DataGrid1.EditCommand
                '编辑    

                DataGrid1.EditItemIndex   =   e.Item.ItemIndex
                Label1.Text   =   DataGrid1.CurrentPageIndex
                btnSelect.Enabled   =   False