Ignore class attributes using Datamember C#

Question

I’m trying to return a json from a controller by ignoring some of the fields in it.

Controller:

    [HttpGet]
    public IActionResult Get()
    {
        var result = _service.Generate();

        if (result == null)
            BadRequest();

        return Json(result);
    }

My service returns a view model:

[DataContract]
public class MenuViewMapping
{
    public MenuViewMapping()
    {
        Children = new List<MenuViewMapping>();
    }
    [DataMember]
    public string Id { get; set; }
    [DataMember]
    public string Title { get; set; }
    public string Permissions { get; set; }
    [DataMember]
    public string Url { get; set; }
    public bool VisibleWithNoChild { get; set; }
    [DataMember]
    public List<MenuViewMapping> Children { get; set; }
}

I’m trying to make the fields Permissions and VisibleWithNoChild are ignored when returning Json. My service basically reads a json and assembles the objects to mount a dynamic menu.

It arrives in the controller with all the information, but does not ignore the above attributes.