I'm implementing a web service with a many to many relationship, but the GET method throws me the following error:
System.Runtime.Serialization.SerializationException: 'The expected kind 'System.Collections.Generic.List'1 [[WebApplication3.ViewModel.ActivitiesViewModel, Models, Version = 1.0.0.0, Culture = neutral, PublicKeyToken = null]] 'with the name of the data contract 'ArrayOfActivitiesViewModel: link '. If you are using DataContractSerializer, try using DataContractResolver or add statically not known types to the list of known types (for example, using the attribute KnownTypeAttribute or adding them to the list of known types that are pass to DataContractSerializer). '
Investigating a bit I find that you have to put the attribute [KnownType(typeof(Subclase)] in the entities but I can not correct the error with that.