Dim pb As Object = Nothing

 If radCars.Checked = True Then

     Dim productBase As ProductsBase(Of CarColumns)
     productBase = New Cars(fileLocation)

     pb = productBase

  ElseIf radTrucks.Checked = True Then

     Dim productBase As ProductsBase(Of TruckColumns)
     productBase = New Truck(fileLocation)

     pb = productBase

  End If

  pb.Parse()
  pb.AddRows()
  ....

Public MustInherit Class ProductsBase(Of T)

    Sub New(filePathString As String)
        FilePath = filePathString
    End Sub

    MustOverride Sub Parse()
    MustOverride Sub DeleteRows()
    MustOverride Sub AddRows(ByVal rows As IEnumerable(Of T), pageNumber As Integer)

    Property ParseResult As ProductLookupContainer(Of T)

End Class

Public Class Cars
    Inherits ProductsBase(Of CarColumns)

    Sub New(filePath As String)
        MyBase.New(filePath)
    End Sub

    Public Overrides Sub AddRows(rows As IEnumerable(Of CarColumns), pageNumber As Integer)
        DatabaseHelper.AddItemsToDB(Of CarProduct)(ConnectionString, rows, pageNumber)
    End Sub

    Public Overrides Sub DeleteRows()
        DatabaseHelper.DeleteRows(ConnectionString, "CarProducts")
    End Sub

    Public Overrides Sub Parse()

        Dim pf As New ParseFile(FilePath)
        Dim result = New ProductLookupContainer(Of CarColumns)
        result = pf.ParseCars

       'Set object
       ParseResult = result

    End Sub

End Class

Public Interface IProducts

    Sub DeleteRows()
    Sub Parse()

End Interface

Public Class ProductsFactory

    Public Shared Function CreateTruck(fileLocation as string) As IProducts
         Return New Truck(fileLocation)
    End Function

    Public Shared Function CreateCar(fileLocation as string) As IProducts
         Return New Car(fileLocation)
    End Function

End Class

Dim pb As IProducts

  If radCars.Checked = True Then
     pb = ProductsFactory.CreateCar(fileLocation)
  ElseIf radTrucks.Checked = True Then
     pb = ProductsFactory.CreateTruck(fileLocation)
  End If

  pb.Parse()
  pb.AddRows()