ASP.NET

<br />
 Protected Sub AddToCart(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAdd.Click<br />
    <br />
  Dim objDT As System.Data.DataTable<br />
    Dim objDR As System.Data.DataRow<br />
<br />
    objDT = Session("Cart")<br />
        Dim Product = ddlProducts.SelectedItem.Text<br />
        Dim blnMatch As Boolean = False<br />
<br />
        For Each objDR In objDT.Rows  <big><-------this is were the exception occurs!!!!!!</big><br />
            If objDR("Product") = Product Then<br />
                objDR("Quantity") += txtQuantity.Text<br />
                blnMatch = True<br />
                Exit For<br />
            End If<br />
        Next<br />
<br />
        If Not blnMatch Then<br />
            objDR = objDT.NewRow<br />
            objDR("Quantity") = txtQuantity.Text<br />
            objDR("Product") = ddlProducts.SelectedItem.Text<br />
            objDR("Cost") = Decimal.Parse(ddlProducts.SelectedItem.Value)<br />
            objDT.Rows.Add(objDR)<br />
        End If<br />
        Session("Cart") = objDT<br />
<br />
        dg.DataSource = objDT<br />
        dg.DataBind()<br />
<br />
        lblTotal.Text = "$" & GetItemTotal()<br />
    End Sub<br />