Entity framework doesn't generate JsonIgnoreAttribute

Question

I'm trying to return from MVC 4 web api ApiController objects generated from entity framework 4 edmx, with accept:json/application.

The problem is json formatter returns also the Navigation Properties, which I don't want to return (I want to return only the Primitive Properties).

So I've looked in the entity framework 4 code generated, in the Navigation Properties, and there are only XmlIgnoreAttribute and SoapIgnoreAttribute while I need JsonIgnoreAttribute.

I cannot change the code generated because it will be overwritten in the next change to the edmx, so how can I configure that the model generation will be produced with JsonIgnoreAttribute?

Thank you

Darin Dimitrov · Accepted Answer · 2012-09-23 14:27:53Z

3

While I don't know if this is a bug or unsupported feature I would recommend you to define view models and have your API controller actions return view models instead of your EF autogenerated domain models. The view models will obviously contain only the properties that you want to expose. A single view model could represent the aggregation of multiple domain models. So don't rely on any XmlIgnore, SoapIgnore, JsonIgnore, ... attributes. Rely on your view models.

answered Sep 23, 2012 at 14:27

Darin Dimitrov

1.0m277 gold badges3.3k silver badges3k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

usr Over a year ago

Yes! Entities are not really suitable for serialization and other kinds of transport.

ozba · Accepted Answer · 2012-09-23 14:56:45Z

Ok, I found out what to do. We need to use custom DefaultContractResolver in this way:

public class ExcludeEntityKeyContractResolver : DefaultContractResolver
{
    private static Type mCollectionType = typeof(System.Data.Objects.DataClasses.RelatedEnd);

    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
    {
        var members = GetSerializableMembers(type);

        IList<JsonProperty> properties = base.CreateProperties(type, memberSerialization);
        IList<JsonProperty> serializeProperties = new List<JsonProperty>();

        for (int i = 0; i < properties.Count; i++)
        {
            var memberInfo = members.Find(p => p.Name == properties[i].PropertyName);
            if (!memberInfo.GetCustomAttributes(false).Any(a => a is SoapIgnoreAttribute) && properties[i].PropertyType != typeof(System.Data.EntityKey))
            {
                serializeProperties.Add(properties[i]);
            }
        }
        return serializeProperties;
    }
}

and in Global.asax:

        JsonSerializerSettings serializerSettings = new JsonSerializerSettings();
        serializerSettings.ContractResolver = new ExcludeEntityKeyContractResolver();
        var jsonMediaTypeFormatter = new JsonMediaTypeFormatter();
        jsonMediaTypeFormatter.SerializerSettings = serializerSettings;
        GlobalConfiguration.Configuration.Formatters.Insert(0, jsonMediaTypeFormatter);

and don't worry about performance, as CreateProperties will only be called once for every type for the whole application duration :)

Exactly what I was looking for. Thanks for this solution. Painstakingly creating models for DTOs is a waste of time in most cases for my projects.

Collectives™ on Stack Overflow

Entity framework doesn't generate JsonIgnoreAttribute

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related