Serialize only interface properties to JSON with Json.net

Question

With a simple class/interface like this

public interface IThing
{
    string Name { get; set; }
}

public class Thing : IThing
{
    public int Id { get; se         


        

Answer 1

Improved version with nested interfaces + support for xsd.exe objects

Yet another variation here. The code came from http://www.tomdupont.net/2015/09/how-to-only-serialize-interface.html with the following improvements over other answers here

• Handles hierarchy, so if you have an Interface2[] within an Interface1 then it will get serialized.

• I was trying to serialize a WCF proxy object and the resultant JSON came up as {}. Turned out all properties were set to Ignore=true so I had to add a loop to set them all to not being ignored.

  public class InterfaceContractResolver : DefaultContractResolver
  {
      private readonly Type[] _interfaceTypes;
  
      private readonly ConcurrentDictionary _typeToSerializeMap;
  
      public InterfaceContractResolver(params Type[] interfaceTypes)
      {
          _interfaceTypes = interfaceTypes;
  
          _typeToSerializeMap = new ConcurrentDictionary();
      }
  
      protected override IList CreateProperties(
          Type type,
          MemberSerialization memberSerialization)
      {
          var typeToSerialize = _typeToSerializeMap.GetOrAdd(
              type,
              t => _interfaceTypes.FirstOrDefault(
                  it => it.IsAssignableFrom(t)) ?? t);
  
          var props = base.CreateProperties(typeToSerialize, memberSerialization);
  
          // mark all props as not ignored
          foreach (var prop in props)
          {
              prop.Ignored = false;
          }
  
          return props;
      }
  }