Automatically generated POCO serialization with task DataContractSerializer and MetaDataTypeAttribute

As the name says, I am having some problems serializing my automatically created POCO objects. But first, some information:

I created my data access level using EF 4.0 en ADO.Net POCO Entity Generator by following this guide: http://blogs.msdn.com/b/adonet/archive/2010/01/25/walkthrough-poco-template -for-the-entity-framework.aspx .

I now have 2 class libraries, one with an EF model and the second with T4 Auto generated POCO objects.

I am currently working on another project where I want to use DAL class libraries. I have to get some objects and serialize them in XML. At first I tried XmlSerializer, but then I found out that it has problems with circulation links. I fixed this problem with XmlIgnore, but then I had a serialization problem:

Public Overridable Property NwlGroup As ICollection(Of NwlGroup) 

Because XmlSerializer does not support interfaces.

Second, I tried a DataContractSerializer with the [DataContract] and [DataMember] attributes in a Poco Class file with an auto-generated entity. This worked, but naturally, I had to clear the changes from the automatically generated file, so I wanted to use the MetaDataType attribute. I created an additional file as follows:

Imports System.Runtime.Serialization
Imports System.ComponentModel.DataAnnotations

<MetadataType(GetType(NewsletterCustomerMetadata))>
Partial Public Class NewsletterCustomer
End Class

<DataContract()
Public Class NewsletterCustomerMetadata

    <DataMember(Name:="emailaddress", IsRequired:=True)>
    Public Overridable Property Emailaddress As String

    <DataMember(Name:="name")>
    Public Overridable Property Name As String

    <DataMember()>
    Public Overridable Property NwlGroup As ICollection(Of NwlGroup)
End Class

Auto generated file:

'------------------------------------------------------------------------------
' <auto-generated>
'     This code was generated from a template.
'
'     Changes to this file may cause incorrect behavior and will be lost if
'     the code is regenerated.
' </auto-generated>
'------------------------------------------------------------------------------
Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports System.Collections.Specialized
Imports System.Runtime.Serialization



Public Class NewsletterCustomer
#Region "Primitive Properties"

    Public Overridable Property ID As Integer

    Public Overridable Property Emailaddress As String

    Public Overridable Property Name As String

...

#Region "Navigation Properties"
    Public Overridable Property NwlGroup As ICollection(Of NwlGroup)
        Get
            If _nwlGroup Is Nothing Then
                Dim newCollection As New FixupCollection(Of NwlGroup)
                AddHandler newCollection.CollectionChanged, AddressOf FixupNwlGroup
                _nwlGroup = newCollection
            End If
            Return _nwlGroup
        End Get
        Set(ByVal value As ICollection(Of NwlGroup))
            If _nwlGroup IsNot value Then
                Dim previousValue As FixupCollection(Of NwlGroup) = TryCast(_nwlGroup, FixupCollection(Of NwlGroup))
                If previousValue IsNot Nothing Then
                    RemoveHandler previousValue.CollectionChanged, AddressOf FixupNwlGroup
                End If
                _nwlGroup = value
                Dim newValue As FixupCollection(Of NwlGroup) = TryCast(value, FixupCollection(Of NwlGroup))
                If newValue IsNot Nothing Then
                    AddHandler newValue.CollectionChanged, AddressOf FixupNwlGroup
                End If
            End If
        End Set
    End Property
    Private _nwlGroup As ICollection(Of NwlGroup)

...
End Class

Then I try to serialize it in xml

    Dim ctx = New ModelEntities(_connectionString)
       ctx.ContextOptions.ProxyCreationEnabled = False
       ctx.ContextOptions.LazyLoadingEnabled = False

    Dim customers = From c In ctx.NwlCustomer
                    Select c
                   Where c.SiID = 99

    Dim filename As String = "C:\test.txt"
    Dim result As NewsletterCustomer = customers.ToList.FirstOrDefault
    Dim writer As New FileStream(filename, FileMode.Create)
    Dim ser As New DataContractSerializer(GetType(NewsletterCustomer))
    ser.WriteObject(writer, customers.ToList.FirstOrDefault)
    writer.Close()

NewsletterCustomer xml /, , , DataContract. DataContract NewsletterCustomerMetadata NewsletterCustomer, root node, , DataContract DataMember.

, DataContractSerializer MetaDataType.

:

• POCO CUSTOM XML?
• [DataContract] [DataMember] POCO?
• Auto Generated POCO XML?