Weird issue with System.NullRefe renceException

[Shannon]

I am having a very strange issue with my asp.net application. I have
created a datagrid which dynamically gets populated from a person
choosing a value from a dropdown list and entering a quantity into a
text box (a simple version of a shopping cart). When I run/debug the
web page using the localhost in the page URL
(http://localhost/mypage.aspx), the datagrid updates properly when a
command button is clicked and all is well. However, when I run the web
page using the machinename (http://mymachine/mypage.aspx) I recieve the
error "Object Reference not Set...System.Nu llReferenceExce ption" when I
click the command button to update the datagrid with new values. Does
anyone have a solution as to why it works as localhost but does not as
machinename? And does anyone have a solution? Thanks in advance.
Shannon

[Ciaran]

I think it would be helpful if you posted the code behind up.

Ciaran

"Shannon" <sh************ @state.co.us> wrote in message
news:11******** *************@c 13g2000cwb.goog legroups.com...

I am having a very strange issue with my asp.net application. I have
created a datagrid which dynamically gets populated from a person
choosing a value from a dropdown list and entering a quantity into a
text box (a simple version of a shopping cart). When I run/debug the
web page using the localhost in the page URL
(http://localhost/mypage.aspx), the datagrid updates properly when a
command button is clicked and all is well. However, when I run the web
page using the machinename (http://mymachine/mypage.aspx) I recieve the
error "Object Reference not Set...System.Nu llReferenceExce ption" when I
click the command button to update the datagrid with new values. Does
anyone have a solution as to why it works as localhost but does not as
machinename? And does anyone have a solution? Thanks in advance.
Shannon

[Shannon]

Here is the requested code behind.

Imports System.Data.Sql Client
Public Class merchandise
Inherits System.Web.UI.P age

#Region " Web Form Designer Generated Code "

'This call is required by the Web Form Designer.
<System.Diagnos tics.DebuggerSt epThrough()> Private Sub
InitializeCompo nent()

End Sub
Protected WithEvents lblNavBar As System.Web.UI.W ebControls.Labe l
Protected WithEvents lblMerchandise As
System.Web.UI.W ebControls.Labe l
Protected WithEvents merTXT1 As System.Web.UI.W ebControls.Labe l
Protected WithEvents merTXT2 As System.Web.UI.W ebControls.Labe l
Protected WithEvents ddProducts As
System.Web.UI.W ebControls.Drop DownList
Protected WithEvents txtQty As System.Web.UI.W ebControls.Text Box
Protected WithEvents Label1 As System.Web.UI.W ebControls.Labe l
Protected WithEvents Label2 As System.Web.UI.W ebControls.Labe l
Protected WithEvents btnCart As
System.Web.UI.W ebControls.Link Button
Protected WithEvents dgCart As System.Web.UI.W ebControls.Data Grid
Protected WithEvents lblTotal As System.Web.UI.W ebControls.Labe l

'NOTE: The following placeholder declaration is required by the Web
Form Designer.
'Do not delete or move it.
Private designerPlaceho lderDeclaration As System.Object

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeCompo nent()
End Sub

#End Region
Public objDT As System.Data.Dat aTable
Public objDR As System.Data.Dat aRow

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load
If Not Page.IsPostBack Then
Dim dbConn As New
SqlConnection(C onfigurationSet tings.AppSettin gs("ConnectRWDa ta"))

'retrieve the data from the database for the List Box
Content
Dim daMerchandise As New SqlDataAdapter( "SELECT prodTYPE,
prodCOST, prodTYPE + ' - $' + CAST(prodCOST AS char(5)) AS prodLIST
FROM tblProducts", dbConn)

'fill the dataset
Dim dsmerchandise As New DataSet
daMerchandise.F ill(dsMerchandi se, "tblProduct s")

'fill the list box with the values.
ddProducts.Data Source = dsmerchandise.T ables("tblProdu cts")
ddProducts.Data TextField = "prodLIST"
ddProducts.Data ValueField = "prodCOST"
ddProducts.Data Bind()

'create the dynamic shopping cart table
makeCart()
End If
End Sub

Function makeCart()

objDT = New System.Data.Dat aTable("Cart")
objDT.Columns.A dd("ID", GetType(Integer ))
objDT.Columns(" ID").AutoIncrem ent = True
objDT.Columns(" ID").AutoIncrem entSeed = 1

objDT.Columns.A dd("Quantity", GetType(Integer ))
objDT.Columns.A dd("Product", GetType(String) )
objDT.Columns.A dd("Cost", GetType(Decimal ))

Session("Cart") = objDT
End Function

Public Sub AddToCart(ByVal s As Object, ByVal e As EventArgs)
objDT = Session("Cart")

Dim Product = ddProducts.Sele ctedItem.Text

objDR = objDT.NewRow 'this is the line creating the error when
run under machinename
objDR("Quantity ") = txtQty.Text
objDR("Product" ) = ddProducts.Sele ctedItem.Text
objDR("Cost") = Decimal.Parse(d dProducts.Selec tedItem.Value)
objDT.Rows.Add( objDR)
Session("Cart") = objDT

dgCart.DataSour ce = objDT
dgCart.DataBind ()

End Sub
End Class