JSON.NET Error Self referencing loop detected for type

You are getting this error of self referencing loop because probably there are two classes which are referencing each other using foreign Key and it is quite common error of JSON when you are using .Edmx(without it also you may get issue).

You can resolve this issue by placing this code in Application_Start()

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Serialize;

It should resolve your issue, and will not throw error

Or For Single JsonConvert with an overload:

JsonConvert.SerializeObject(YourObject, Formatting.Indented,
    new JsonSerializerSettings() {
        ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore
    }
);

Any of the above method will resolve your issue.

For .NET Core

If you are using .NET Core(3), in starup.cs you will need to add Code as below

services.AddMvc()
    .AddJsonOptions(
        options => options.SerializerSettings.ReferenceLoopHandling =            
        Newtonsoft.Json.ReferenceLoopHandling.Ignore
    );

Using JSONIgnore Attribute

You will need to install Json.NET from nuget and add the [JsonIgnore] attribute to the virtual property in the class

Something like below:

    public string Name { get; set; }
    public string Description { get; set; }
    public Nullable<int> Order_ID { get; set; }

    [JsonIgnore]
    public virtual Orders Order { get; set; }

Thanks.

This may help you

public DBContext() : base("name=DBContext") 
{ 
    Database.SetInitializer(new DBContexttDataInitializer()); 
    this.Configuration.LazyLoadingEnabled = false; 
    this.Configuration.ProxyCreationEnabled = false; 
} 

http://code.msdn.microsoft.com/Loop-Reference-handling-in-caaffaf7

Or  If using ASP.NET Core MVC, add this to the ConfigureServices method of your startup.cs file:

services.AddMvc()
    .AddJsonOptions(
        options => options.SerializerSettings.ReferenceLoopHandling =            
        Newtonsoft.Json.ReferenceLoopHandling.Ignore
    );