การทำ เพิ่ม ลบ แก้ไข ในหน้าเดียวกัน ผมทำการเรียก อีเวน Rowupdating แต่มันไม่ทำงานคับ

Dim db As New DB
    Dim dt As New DataTable

    Sub DisplayZone()

        Response.Write(Now.Second)
        Dim sql As String
        sql = "Select * From tb_zone"
        dt = db.QueryDataTable(sql)
        GV.DataSource = dt
        GV.DataBind()
    End Sub

    Protected Sub GV_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles GV.Load
        If Not Page.IsPostBack Then
            DisplayZone()
        End If

    End Sub

    Protected Sub GV_RowCancelingEdit(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCancelEditEventArgs) Handles GV.RowCancelingEdit
        GV.EditIndex = -1
        GV.ShowFooter = True
        DisplayZone()
    End Sub

    Protected Sub GV_RowEditing(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles GV.RowEditing
        GV.EditIndex = e.NewEditIndex
        DisplayZone()
    End Sub

    Protected Sub GV_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles GV.RowUpdating
        DisplayZone()
    End Sub