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Speed Up Your Reflection Processes

  • October 28, 2008
  • By Paul Kimmel
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Introduction

I write about real problems that real programmers have, and in so doing I try to show you, the reader, alternate solutions that provide you with options. Hearing back from you that the article and solution helped makes it worth writing.

All of us use Reflection implicitly when objects are serialized. Many use Reflection explicitly to do things like deep object copies or dumping object state. The upside of Reflection is it that it supports writing a general purpose algorithm, albeit an underperforming one. In this article, you will learn to write a general purpose emitter that you need write only one time, and the emitter outputs a specific-purpose algorithm. In this example, the algorithm emits code that dumps the object state for a specific list of objects. Pass in the list of objects and the emitter writes the equivalent of a property-by-property state dump. A side benefit of working at this level, besides writing highly performant code, is that you can learn a little more about how .NET works under the hood.

Here Is the Sample Main Subroutine...

The sample Main subroutine is listed here without much fanfare. It is very simple but you need it to try the emitter. Listing 2 contains the definition of the Customer class.

Listing 1: A sample Main loop that invokes and tests the emitter.

Module Module1

   Sub Main()

      ' Create customer list
      Dim customers As List(Of Customer) = New List(Of Customer)
      For i As Integer = 0 To 50
         customers.Add(New Customer(i.ToString()))
      Next

      DynamicAssemblyCreator.CreateAssembly(customers)
      Console.ReadLine()

   End Sub
End Module

Listing 2: The Customer class represents a custom coded entity that mirrors the Northwind.Customers table.

Public Class Customer

   ''' <summary>
   ''' Initializes a new instance of the Customer class.
   ''' </summary>
   ''' <param name="customerID"></param>
   Public Sub New(ByVal customerID As String)
      FCustomerID = customerID
      FCompanyName = "Company " & customerID.ToString()
      FContactName = "George Contact"
      FContactTitle = "Dr."
   End Sub

   Private FCustomerID As String = ""
   Public Property CustomerID() As String
      Get
         Return FCustomerID
      End Get
      Set(ByVal Value As String)
         FCustomerID = Value
      End Set
   End Property

   Private FCompanyName As String
   Public Property CompanyName() As String
      Get
         Return FCompanyName
      End Get
      Set(ByVal Value As String)
         FCompanyName = Value
      End Set
   End Property

   Private FContactName As String = ""
   Public Property ContactName() As String
      Get
         Return FContactName
      End Get
      Set(ByVal Value As String)
         FContactName = Value
      End Set
   End Property

   Private FContactTitle As String = ""
   Public Property ContactTitle() As String
      Get
         Return FContactTitle
      End Get
      Set(ByVal Value As String)
         FContactTitle = Value
      End Set
   End Property

   Private FAddress As String = ""
   Public Property Address() As String
      Get
         Return FAddress
      End Get
      Set(ByVal Value As String)
         FAddress = Value
      End Set
   End Property

   Private FCity As String = ""
   Public Property City() As >String
      Get
         Return FCity
      End Get
      Set(ByVal Value As String)
         FCity = Value
      End Set
   End Property

   Private FRegion As String = ""
   Public Property Region() As String
      Get
         Return FRegion
      End Get
      Set(ByVal Value As String)
         FRegion = Value
      End Set
   End Property

   Private FPostalCode As String = ""
   Public Property PostalCode() As String
      Get
         Return FPostalCode
      End Get
      Set(ByVal Value As String)
         FPostalCode = Value
      End Set
   End Property

   Private FCountry As String = ""
   Public Property Country() As String
      Get
         Return FCountry
      End Get
      Set(ByVal Value As String)
         FCountry = Value
      End Set
   End Property

   Private FPhone As String = ""
   Public Property Phone() As String
      Get
         Return FPhone
      End Get
      Set(ByVal Value As String)
         FPhone = Value
      End Set
   End Property

   Private FFax As String = ""
   Public Property Fax() As String
      Get
         Return FFax
      End Get
      Set(ByVal Value As String)
         FFax = Value
      End Set
   End Property
End Class

You will need Main and the Customer class to try the demo. You can just copy and paste them, but if you are just getting started writing the code yourself will provide you with some good practice.





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