Join the social network of Tech Nerds, increase skill rank, get work, manage projects...
 
  • Solution for "Self referencing loop detected" error in Entity Framework

    • 0
    • 0
    • 0
    • 0
    • 2
    • 0
    • 0
    • 0
    • 414
    Comment on it

    Few days ago, I was creating an ASP.NET Web API by generating Entity Framework scaffolding API controller. There were simply two tables in the database Product and Title. In the edmx file, the auto-generated classes were as follows:
     

    public partial class Product
    {
        public Product()
        {
            this.Titles = new HashSet<Title>();
        }
        
        public long ID { get; set; }
        public string Name { get; set; }
        public string ItemCode { get; set; }
        public string StatusCode { get; set; }
        public string Description { get; set; }
        
        public virtual ICollection<Title> Titles { get; set; }
    }

     

    public partial class Title
    {
        public long ProductID { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        
        public virtual Product Product { get; set; }
    }

     

    In the ApiController file, I had a Get method which returned Parent (Product) and Child (Title) data. The definition for Get method is as follows.
     

    public IEnumerable<Product> Get()
    {
        return entities.Products.Include(x => x.Titles).AsEnumerable();
    }

     

    Just after I hit Web API URL in the browser, I started getting following error message.


    Error Message

    The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; charset=utf-8'.
    
    Self referencing loop detected for property 'Product' with type 'System.Data.Entity.DynamicProxies.Product_51E58E5D9B59C792A692C1D0BD14B81033E09B8451A77CDC684C1AA673008663'. Path '[0].Titles[0]'.

     

    This issue was occurring because I was trying to serialize the Entity Framework object directly. Since Product have Titles and the Titles have a reference back to Product, it cannot be serialized. After spending some time, I found the solution which required me to add following lines in Application_Start() method in Global.asax.cs file.
     

    Solution

    HttpConfiguration config = GlobalConfiguration.Configuration;
    
    config.Formatters.JsonFormatter
                .SerializerSettings
                .ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;


    Here we have defined global setting for JSON.Net serializer to ignore circular references.

 2 Comment(s)

Sign In
                           OR                           
                           OR                           
Register

Sign up using

                           OR                           
Forgot Password
Fill out the form below and instructions to reset your password will be emailed to you:
Reset Password
Fill out the form below and reset your password: