Visual Basic 2010 : Serialization in the ADO.NET Entity Framework

6/14/2011 9:16:17 AM

When you create Entity Data Models, entities are automatically decorated with Serializable and DataContract attributes and their members as DataMember as you can easily check by investigating the code-behind file for EDMs. This enables binary and Xml serialization for entities also in WCF scenarios. To understand how this works, create a new console project and add a new EDM wrapping the Northwind database , including only the Customers and Orders tables. Basically you use formatters as you did in the objects serialization with no differences. Code in Listing 1 shows how to accomplish this.

Listing 1. Serializing Entities from an Entity Data Model

Imports System.Runtime.Serialization.Formatters.Binary
Imports System.IO

Module Module1
    Sub Main()
        Using northwind As New NorthwindEntities
            'Retrieves the first order, as an example
            Dim anOrder As Order = northwind.Orders.Include("Customer").First

            'Same as classic objects serialization
            Dim formatter As New BinaryFormatter
            Using stream As New FileStream("C:\temp\EFSerialization.dat",
                                FileMode.Create)
                formatter.Serialize(stream, anOrder)
            End Using

            Dim newOrder As Order
            Using source As New FileStream("C:\temp\EFSerialization.dat",
                                FileMode.Open)
                newOrder = CType(formatter.Deserialize(source), Order)
            End Using
        End Using

        Console.ReadLine()
    End Sub
End Module