asp.net update ข้อมูลไม่ได้ ไม่เก็บข้อมูลที่กรอกเข้าไปใหม่

Public Class estudent
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If IsNothing(Session("strCustomerID")) Then
            Response.Redirect("index.aspx")
            Response.End()
        End If
        Dim cls As New clsGetCustomer.getCustomer
        Dim myArr As Array = cls.resultCustomer(Session("strCustomerID"))
        If myArr.Length > 0 Then
            Me.lblCustomerID.Text = DataBinder.Eval(myArr(0), "username").ToString()
            Session("department") = Me.lblCustomerID.Text
        End If
        Dim iIndex As Integer
        Dim strJobCode() As String
        Dim sb As StringBuilder = New StringBuilder
        Dim strGet As String = Request.QueryString("stid")
        If strGet <> Nothing Then
            strJobCode = strGet.Split(",")
            For iIndex = 0 To strJobCode.Length - 1
                sb.Append(strJobCode(iIndex) & "<br>")
                Session("stid") = sb.ToString
            Next
            'Response.Write(sb.ToString)
        End If

        Dim cls2 As New clsStid.getCustomer
        Dim myArr2 As Array = cls2.resultStid(Session("stid"))
        If myArr2.Length > 0 Then
            Me.lblStid.Text = DataBinder.Eval(myArr2(0), "stid").ToString()
            Me.txtNaid.Text = DataBinder.Eval(myArr2(0), "stidp").ToString()
            Me.txtName.Text = DataBinder.Eval(myArr2(0), "stname").ToString()
            Me.txtSur.Text = DataBinder.Eval(myArr2(0), "stsurname").ToString()
            Me.lblDep.Text = DataBinder.Eval(myArr2(0), "stdep").ToString()
            Me.txtAdd.Text = DataBinder.Eval(myArr2(0), "stadd").ToString()
            Me.txtTel.Text = DataBinder.Eval(myArr2(0), "sttel").ToString()
            Me.txtMail.Text = DataBinder.Eval(myArr2(0), "stmail").ToString()
            Me.txtTa.Text = DataBinder.Eval(myArr2(0), "stta").ToString()

        End If
    End Sub
    Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSave.Click
        Dim cls As New clsUpst.UpdateCustomer()
        Dim myArr As Array = cls.saveUpdateStudent(Session("stid"), _
                                                    Me.txtNaid.Text, _
                                                    Me.txtName.Text, _
                                                    Me.txtSur.Text, _
                                                    Me.lblDep.Text, _
                                                    Me.txtAdd.Text, _
                                                    Me.txtTel.Text, _
                                                    Me.txtMail.Text, _
                                                    Me.txtTa.Text)

        If CStr(myArr(0)) = "1" Then
            Me.ClientScript.RegisterStartupScript(Me.GetType(), "myalert", "alert('Update Successfully ');window.location='student.aspx';", True)
        Else
            Me.ClientScript.RegisterStartupScript(Me.GetType(), "myalert", "alert('Update Failed error..." & Replace(myArr(1), "'", "\'") & "');", True)
        End If

    End Sub
  

End Class