YamlDotNet - Serialization of Guid properties generates empty brackets - vb.net

Question

I am using YamlDotNet library to serialize some objects in Yaml. I've met some problems with the serialization of Guid properties.
Serialization of Guid properties generates empty brackets ( ex: {} )
See code below
Dim l As New List(Of Person)
l.Add(New Person() With {.Firstname = "MyFirstName", .Lastname = "MyLastName", .Id = Guid.NewGuid()})
Using sw As New StreamWriter("output.yaml", False)
Dim serializer = New Serializer()
serializer.Serialize(sw, l)
End Using
this code will output :
- Id: {}
Firstname: MyFirstName
Lastname: MyLastName
With the class:
Public Class Person
Public Property Id As Guid
Public Property Frstname As String
Public Property Lastname As String
End Class
Am I missing something or is this an issue of the library ?

Answer 1

You can define a custom converter to use when you need to customize the serialization of a type. The converter needs to implement IYamlTypeConverter, and be registered on the Serializer or Deserializer. Here is an example of such a converter:
Public Class GuidConverter
Implements IYamlTypeConverter
Public Function Accepts(type As Type) As Boolean Implements IYamlTypeConverter.Accepts
Return type = GetType(Guid)
End Function
Public Function ReadYaml(parser As IParser, type As Type) As Object Implements IYamlTypeConverter.ReadYaml
Dim reader = New EventReader(parser)
Dim scalar = reader.Expect(Of Scalar)()
Return Guid.Parse(scalar.Value)
End Function
Public Sub WriteYaml(emitter As IEmitter, value As Object, type As Type) Implements IYamlTypeConverter.WriteYaml
emitter.Emit(New Scalar(value.ToString()))
End Sub
End Class
The usage is quite simple:
Dim serializer = New Serializer()
serializer.RegisterTypeConverter(New GuidConverter())
serializer.Serialize(Console.Out, New With {.id = Guid.NewGuid()})
You can see a fully working example here.