Question

I’m a novice at serialization and I’ve run into a problem. I have a REST service that returns an array of IDDescriptionPair objects. When consuming the service, I’m using the “Paste XML as Types” VS add-in to create an object. I’m only modifying this object to add the DataContract attribute so my namespaces match on each end. Here’s that object:

Imports System.Runtime.Serialization

<DataContract([Name]:="IDDescriptionPair", [Namespace]:="http://schemas.datacontract.org/2004/07/Blizzard.ClassLibrary")>
<System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.225"), _
 System.Diagnostics.DebuggerStepThroughAttribute(), _
 System.Xml.Serialization.XmlTypeAttribute([Namespace]:="http://schemas.datacontract.org/2004/07/Blizzard.ClassLibrary"), _
 System.Xml.Serialization.XmlRootAttribute   ([Namespace]:="http://schemas.datacontract.org/2004/07/Blizzard.ClassLibrary", IsNullable:=True)> _
Partial Public Class IDDescriptionPair

  Private descriptionField As String

  Private idField As Integer

  Private idFieldSpecified As Boolean

  '''<remarks/>
  <System.Xml.Serialization.XmlElementAttribute(IsNullable:=True)> _
  Public Property Description() As String
    Get
      Return Me.descriptionField
    End Get
    Set(value As String)
      Me.descriptionField = value
    End Set
  End Property

  '''<remarks/>
  Public Property ID() As Integer
    Get
      Return Me.idField
    End Get
    Set(value As Integer)
      Me.idField = value
    End Set
  End Property

  '''<remarks/>
  <System.Xml.Serialization.XmlIgnoreAttribute()> _
  Public Property IDSpecified() As Boolean
    Get
      Return Me.idFieldSpecified
    End Get
    Set(value As Boolean)
      Me.idFieldSpecified = value
    End Set
  End Property
End Class

I can call the service and deserialize the object, and it appears to work fine. I get a list of the correct number of IDDescriptionPair objects. The problem is that they’re all blank – none of the properties are populated.

Here’s the code where I consume the service:

Dim client As New HttpClient()
Dim endpoint As New Uri("http://bmpscnt410a/services/v1/personservices/offices/5/principals")

Using response As HttpResponseMessage = client.Get(endpoint)
  response.EnsureStatusIsSuccessful()

  Dim idp As List(Of IDDescriptionPair)
  Try
    idp = response.Content.ReadAsDataContract(Of List(Of IDDescriptionPair))()
  Catch ex As Exception
  End Try
End Using

I’ve tried using DataContractSerializer directly, but I get the same result (which is expected, I guess). Any ideas would be appreciated.

Answer 1

The type which you use is a XmlSerializer type (annotated with attributes from the System.Xml.Serialization namespace, such as <XmlType()>, <XmlRoot()> and so on). For that you’ll need to use the XmlSerializer to deserialize that. If you include (Import) the namespace System.Xml.Serialization, you should get the extension methods ReadAsXmlSerializable, which is what you should be using to deserialize the response.