Column invisibile

[ice_wind]

ho questo codice:

<script runat="server">
Dim objDT As System.Data.DataTable 
Dim objDR As System.Data.DataRow

Private Sub Page_Load(s As Object, e As EventArgs)
     If Not IsPostBack Then
          makeCart()
     End If
End Sub

Function makeCart()
     objDT = New System.Data.DataTable("Cart")
     objDT.Columns.Add("ID", GetType(Integer))
        objDT.Columns("ID").AutoIncrement = True

     objDT.Columns("ID").AutoIncrementSeed = 1

        objDT.Columns.Add("Quantità", GetType(Integer))
        objDT.Columns.Add("Prodotto", GetType(String))
        objDT.Columns.Add("Prezzo", GetType(Decimal))
        
        
     Session("Cart") = objDT
End Function

Sub AddToCart(s As Object, e As EventArgs)
    objDT = Session("Cart")
    Dim Product = ddlProducts.SelectedItem.Text
    Dim blnMatch As Boolean = False

    For Each objDR In objDT.Rows
            If objDR("Prodotto") = Product Then
                objDR("Quantità") += txtQuantity.Text
                blnMatch = True
                Exit For
            End If
    Next

    If Not blnMatch Then
    objDR = objDT.NewRow
            objDR("Quantità") = txtQuantity.Text
            objDR("Prodotto") = ddlProducts.SelectedItem.Text
            objDR("Prezzo") = Decimal.Parse(ddlProducts.SelectedItem.Value)
    objDT.Rows.Add(objDR)
    End If
    Session("Cart") = objDT

    dg.DataSource = objDT
    dg.DataBind()
    
    lblTotal.Text = "$" & GetItemTotal()
End Sub

Function GetItemTotal() As Decimal
    Dim intCounter As Integer
    Dim decRunningTotal As Decimal
    
    For intCounter = 0 To objDT.Rows.Count - 1
        objDR = objDT.Rows(intCounter)
            decRunningTotal += (objDR("Prezzo") * objDR("Quantità"))
    Next
    
    Return decRunningTotal 
End Function

Sub Delete_Item(s As Object, e As DataGridCommandEventArgs)
     objDT = Session("Cart")
     objDT.Rows(e.Item.ItemIndex).Delete()
     Session("Cart") = objDT

     dg.DataSource = objDT
     dg.DataBind()

     lblTotal.Text = "$" & GetItemTotal()
End Sub
</script> 

vorrei che le colonne del id e del prezzo fossero invisibili.. come faccio?!?