Object reference not set to an instance of an object...
Hi,
I have following code to make a shopping cart and when I run it I get an error saying "Object reference not set to an instance of an object" and the error is in this line,
VB Code:
"Line 51: For Each objDR In objDT.Rows"
Its the line in SUB AddToCart...
VB Code:
Private objDT As System.Data.DataTable
Private objDR As System.Data.DataRow
Private Sub Page_Load(ByVal s As Object, ByVal 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("Quantity", GetType(Integer))
objDT.Columns.Add("Product", GetType(String))
objDT.Columns.Add("Cost", GetType(Decimal))
Session("Cart") = objDT
End Function
Sub AddToCart(ByVal s As Object, ByVal e As EventArgs)
objDT = Session("Cart")
Dim Product = ddlProducts.SelectedItem.Text
Dim blnMatch As Boolean = False
For Each objDR In objDT.Rows
If objDR("Product") = Product Then
objDR("Quantity") += txtQuantity.Text
blnMatch = True
Exit For
End If
Next
If Not blnMatch Then
objDR = objDT.NewRow
objDR("Quantity") = txtQuantity.Text
objDR("Product") = ddlProducts.SelectedItem.Text
objDR("Cost") = Decimal.Parse(ddlProducts.SelectedItem.Value)
objDT.Rows.Add(objDR)
End If
Session("Cart") = objDT
dg.DataSource = objDT
dg.DataBind()
lblTotal.Text = "$" & GetItemTotal()
End Sub
Function GetItemTotal() As Decimal
Dim intCounter As Integer
Dim decRunningTotal As Decimal
For intCounter = 0 To objDT.Rows.Count - 1
objDR = objDT.Rows(intCounter)
decRunningTotal += (objDR("Cost") * objDR("Quantity"))
Next
Return decRunningTotal
End Function
Sub Delete_Item(ByVal s As Object, ByVal e As DataGridCommandEventArgs)
objDT = Session("Cart")
objDT.Rows(e.Item.ItemIndex).Delete()
Session("Cart") = objDT
dg.DataSource = objDT
dg.DataBind()
lblTotal.Text = "$" & GetItemTotal()
End Sub
Can anyone tell me how to create an object of this type...???
Cheers...