Adding rows to a datatable while looping through a datagridview

Question

I've got a datagridview populated from a MySQL db. I'm looping through it to validate the info and, when info is validated, adding records to a datatable.

The problem i've got is that my current code only adds the first record. I expected it to add a record, move on and then add another record and move on etc.

Any ideas?

    Private Sub ProcessorWorker_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles ProcessorWorker.DoWork
    Console.WriteLine("ProcessorWorker Invoked...")
    Try
        Dim dt As New DataTable

        Dim entryid As String = " "
        For Each row As DataGridViewRow In orderslist.Rows

            If row.Cells("member_id").Value.ToString IsNot Nothing Then
                entryid = row.Cells("entry_id").Value.ToString
                If entryid <> "" Then
                Dim memberid As String = row.Cells("member_id").Value.ToString

                    Dim cn1 As New MySqlConnection
                    cn1.ConnectionString = ###myconnectionstring###
                    Dim vm_components As New MySqlDataAdapter("Select * FROM website_orders WHERE order_id= '" & entryid & "'", cn1)
                    Dim vm_components_table As New DataTable
                    vm_components.Fill(vm_components_table)
                    Dim row1 As DataRow
                    row1 = vm_components_table.Select("order_id = '" & entryid & "'").FirstOrDefault()
                    If Not row1 Is Nothing Then
                        If row1.Item("cart_id") IsNot Nothing Then web_cartid = row1.Item("cart_id").ToString
                        If row1.Item("email") IsNot Nothing Then web_email = row1.Item("email").ToString
                        If row1.Item("member_id") IsNot Nothing Then web_memberid = row1.Item("member_id").ToString
                        If row1.Item("firstname") IsNot Nothing Then web_firstname = row1.Item("firstname").ToString
                        If row1.Item("lastname") IsNot Nothing Then web_lastname = row1.Item("lastname").ToString
                        If row1.Item("company") IsNot Nothing Then web_company = row1.Item("company").ToString
                        If row1.Item("address1") IsNot Nothing Then web_address1 = row1.Item("address1").ToString
                        If row1.Item("address2") IsNot Nothing Then web_address2 = row1.Item("address2").ToString
                        If row1.Item("city") IsNot Nothing Then web_city = row1.Item("city").ToString
                        If row1.Item("postcode") IsNot Nothing Then web_postcode = row1.Item("postcode").ToString
                    End If

                    dt.Columns.Add("Product Ordered", Type.GetType("System.String"))
                    dt.Columns.Add("Operating System", Type.GetType("System.String"))
                    dt.Columns.Add("Company", Type.GetType("System.String"))
                    dt.Columns.Add("Customer", Type.GetType("System.String"))
                    dt.Columns.Add("Email Address", Type.GetType("System.String"))

                    WebOrders.DataSource = dt
                    Dim dr As DataRow
                    dr = dt.NewRow
                    dr("Product Ordered") = web_servertype
                    dr("Operating System") = web_os
                    dr("Company") = "WORLD"
                    dr("Customer") = web_firstname & " " & web_lastname
                    dr("Email Address") = web_email
                    dt.Rows.Add(dr)
                    WebOrders.AllowUserToAddRows = False
                End If
            End If
        Next

    Catch ex As Exception

    End Try

End Sub

Answer 1

The problem is that you put the add statements inside the for each loop. So in the second iteration you're trying to add an already existing column named Product Ordered to the DataTable . That's why an exception is thrown and you reach the catch block. The solution is to put the add statements before the for each loop.