CODEWITHSUNDEEP
c#asp.netjsonasp.net-web-api
CampDev
CampDev

Reputation: 1659

Failed to serialize the response in Web API with Json

I am working with ASP.NET MVC 5 Web Api. I want consult all my users.

I wrote api/users and I receive this:

"The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; charset=utf-8'"

In WebApiConfig, already I added these lines:

HttpConfiguration config = new HttpConfiguration();
config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType);
config.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;

But it still doesn't work.

My function for return data is this:

public IEnumerable<User> GetAll()
{
    using (Database db = new Database())
    {
        return db.Users.ToList();
    }
}

Upvotes: 118

Views: 247507

Answers (27)

Sayyam abbasi
Sayyam abbasi

Reputation: 109

Just put following lines in global.asax:

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;  
GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);

Import

using System.Data.Entity;

Upvotes: 4

Lapenkov Vladimir
Lapenkov Vladimir

Reputation: 3218

Solution that worked for me:

  1. Use [DataContract] for class and [DataMember] attributes for each property to serialize. This is enough to get Json result (for ex. from fiddler).

  2. To get xml serialization write in Global.asax this code:

    var xml = GlobalConfiguration.Configuration.Formatters.XmlFormatter; xml.UseXmlSerializer = true;

  3. Read this article, it helped me to understand serialization: https://www.asp.net/web-api/overview/formats-and-model-binding/json-and-xml-serialization

Upvotes: 2

Hadi R.
Hadi R.

Reputation: 413

in my case, it was fixed when I removed the virtual keyword before my navigation properties, I mean the reference tables. so I changed 

public virtual MembershipType MembershipType { get; set; }

to:

public MembershipType MembershipType { get; set; }

Upvotes: 0

Yogesh Dangre
Yogesh Dangre

Reputation: 306

You will have to define Serializer Formatter within WebApiConfig.cs available in App_Start Folder like

Adding config.Formatters.Remove(config.Formatters.XmlFormatter); // which will provide you data in JSON Format

Adding config.Formatters.Remove(config.Formatters.JsonFormatter); // which will provide you data in XML Format

Upvotes: 1

Msxmania
Msxmania

Reputation: 53

Use [Serializable] for class:

Example:

[Serializable]
public class UserModel {
    public string Name {get;set;}
    public string Age {get;set;}
}

It worked for me!

Upvotes: 2

MR.S
MR.S

Reputation: 21

Add the below line 

this.Configuration.ProxyCreationEnabled = false;

Two way to use ProxyCreationEnabled as false.

  1. Add it inside of DBContext Constructor

    public ProductEntities() : base("name=ProductEntities")
{
    this.Configuration.ProxyCreationEnabled = false;
}

OR

  1. Add the line inside of Get method

    public IEnumerable<Brand_Details> Get()
{
    using (ProductEntities obj = new ProductEntities())
    {
        this.Configuration.ProxyCreationEnabled = false;
        return obj.Brand_Details.ToList();
    }
}

Upvotes: 2

Catalyst
Catalyst

Reputation: 465

In case: If adding code to WebApiConfig.cs or Global.asax.cs doesn't work for you:

.ToList();

Add .ToList() function.

I tried out every solution but following worked for me:

var allShops = context.shops.Where(s => s.city_id == id)**.ToList()**;
return allShops;

I hope, it helps.

Upvotes: 0

Manuel Sansone
Manuel Sansone

Reputation: 349

In my case I solved recreating the database. I made some changes in a model and launching Update-Database in Package Manager Console I got the following Error:

"The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_dbo.Activities_dbo.Projects_ProjectId". The conflict occurred in database "TrackEmAllContext-20190530144302", table "dbo.Projects", column 'Id'."

Upvotes: 0

Er Suman G
Er Suman G

Reputation: 691

Adding this in your Application_Start() method of Global.asax file should solve the problem

protected void Application_Start()
{
    GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings
        .ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
    GlobalConfiguration.Configuration.Formatters
        .Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter); 
// ...
}

METHOD 2: [Not recommended]
If you are working with EntityFramework, you can disable proxy in your DbContext class constructor. NOTE: this code wll be removed if you update the model

public class MyDbContext : DbContext
{
  public MyDbContext()
  {
    this.Configuration.ProxyCreationEnabled = false;
  }
}

Upvotes: 8

William Hou
William Hou

Reputation: 1781

Visual Studio 2017 or 2019 is totally unthoughtful on this, because Visual Studio itself requires the output to be in json format, while Visual Studio's default format is "XmlFormat" (config.Formatters.XmlFormatter).

Visual Studio should do this automatically instead of giving developers so much trouble.

To correct this problem, go to the WebApiConfig.cs file, and add

var json = config.Formatters.JsonFormatter; json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects; config.Formatters.Remove(config.Formatters.XmlFormatter);

after "config.MapHttpAttributeRoutes();" in the Register(HttpConfiguration config) method. This would allow your project to produce json output.

Upvotes: 0

G&#252;l Eda Aydemir
G&#252;l Eda Aydemir

Reputation: 49

This is my error

I basically add one line which they are

  • entities.Configuration.ProxyCreationEnabled = false;

to UsersController.cs 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using UserDataAccess;

namespace SBPMS.Controllers
{
    public class UsersController : ApiController
    {


        public IEnumerable<User> Get() {
            using (SBPMSystemEntities entities = new SBPMSystemEntities()) {
                entities.Configuration.ProxyCreationEnabled = false;
                return entities.Users.ToList();
            }
        }
        public User Get(int id) {
            using (SBPMSystemEntities entities = new SBPMSystemEntities()) {
                entities.Configuration.ProxyCreationEnabled = false;
                return entities.Users.FirstOrDefault(e => e.user_ID == id);
            }
        }
    }
}

Here is my output:

Upvotes: 1

aemre
aemre

Reputation: 2580

I resolved it using this code to WebApiConfig.cs file

var json = config.Formatters.JsonFormatter;
json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects; 
config.Formatters.Remove(config.Formatters.XmlFormatter);

Upvotes: 11

Maytham Fahmi
Maytham Fahmi

Reputation: 33437

In my case I have had similar error message:

The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.

But when I dig deeper in it, the issue was:

Type 'name.SomeSubRootType' with data contract name 'SomeSubRootType://schemas.datacontract.org/2004/07/WhatEverService' is not expected. Consider using a DataContractResolver if you are using DataContractSerializer or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to the serializer.

The way I solved by adding KnownType.

[KnownType(typeof(SomeSubRootType))]
public partial class SomeRootStructureType

This was solved inspired from this answer.

Reference: https://msdn.microsoft.com/en-us/library/ms730167(v=vs.100).aspx

Upvotes: 1

B Bhatnagar
B Bhatnagar

Reputation: 1816

While all these answers above are correct, one may want to check the InnerException > ExceptionMessage.

If it says something like this "The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.". This could be an issue because of default behavior of the EF.

By assigning LazyLoadingEnabled = false in your DbContext constructor will do the trick.

public class MyDbContext : DbContext
{
  public MyDbContext()
  {
    this.Configuration.LazyLoadingEnabled = false;
  }
}

For more detailed reading about EagerLoading and LazyLoading behavior of EF refer this MSDN Article.

Upvotes: 1

Vanice
Vanice

Reputation: 676

This also happens when the Response-Type is not public! I returned an internal class as I used Visual Studio to generate me the type.

internal class --> public class

Upvotes: 0

Kasper Jensen
Kasper Jensen

Reputation: 622

I don't like this code:

foreach(var user in db.Users)

As an alternative, one might do something like this, which worked for me:

var listOfUsers = db.Users.Select(r => new UserModel
                         {
                             userModel.FirstName = r.FirstName;
                             userModel.LastName = r.LastName;

                         });

return listOfUsers.ToList();

However, I ended up using Lucas Roselli's solution.

Update: Simplified by returning an anonymous object:

var listOfUsers = db.Users.Select(r => new 
                         {
                             FirstName = r.FirstName;
                             LastName = r.LastName;
                         });

return listOfUsers.ToList();

Upvotes: 10

Lucas L Roselli
Lucas L Roselli

Reputation: 2830

If you are working with EF, besides adding the code below on Global.asax

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings
    .ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
GlobalConfiguration.Configuration.Formatters
    .Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);

Dont`t forget to import 

using System.Data.Entity;

Then you can return your own EF Models

Simple as that!

Upvotes: 155

Harish K
Harish K

Reputation: 21

Use the following namespace:

using System.Web.OData;

Instead of :

using System.Web.Http.OData;

It worked for me

Upvotes: 2

Aykut
Aykut

Reputation: 119

public class UserController : ApiController
{

   Database db = new Database();

   // construction
   public UserController()
   {
      // Add the following code
      // problem will be solved
      db.Configuration.ProxyCreationEnabled = false;
   }

   public IEnumerable<User> GetAll()
    {
            return db.Users.ToList();
    }
}

Upvotes: 11

Ogglas
Ogglas

Reputation: 70184

My personal favorite: Just add the code below to App_Start/WebApiConfig.cs. This will return json instead of XML by default and also prevent the error you had. No need to edit Global.asax to remove XmlFormatter etc.

The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8

config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));

Upvotes: 4

Bimal Das
Bimal Das

Reputation: 2002

Add this code to global.asax below on Application_Start:

Update from .Ignore to .Serialize . It must work.

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Serialize;
            GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);

Upvotes: 38

marshall
marshall

Reputation: 11

Another case where I received this error was when my database query returned a null value but my user/view model type was set as non-nullable. For example, changing my UserModel field from int to int? resolved.

Upvotes: 0

Proximo
Proximo

Reputation: 6551

Use AutoMapper...

public IEnumerable<User> GetAll()
    {
        using (Database db = new Database())
        {
            var users = AutoMapper.Mapper.DynamicMap<List<User>>(db.Users);
            return users;
        }
    }

Upvotes: 2

Md. Alim Ul Karim
Md. Alim Ul Karim

Reputation: 2442

Given right answer is one way to go, however it is an overkill when you can fix it by one config settings.

Better to use it in the dbcontext constructor 

public DbContext() // dbcontext constructor
            : base("name=ConnectionStringNameFromWebConfig")
{
     this.Configuration.LazyLoadingEnabled = false;
     this.Configuration.ProxyCreationEnabled = false;
}

Asp.Net Web API Error: The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'

Upvotes: 54

Greg A
Greg A

Reputation: 531

To add to jensendp's answer:

I would pass the entity to a user created model and use the values from that entity to set the values in your newly created model. For example:

public class UserInformation {
   public string Name { get; set; }
   public int Age { get; set; }

   public UserInformation(UserEntity user) {
      this.Name = user.name;
      this.Age = user.age;
   }
}

Then change your return type to: IEnumerable<UserInformation>

Upvotes: 1

Alex
Alex

Reputation: 158

There's also this scenario that generate same error:

In case of the return being a List<dynamic> to web api method

Example:

public HttpResponseMessage Get()
{
    var item = new List<dynamic> { new TestClass { Name = "Ale", Age = 30 } };

    return Request.CreateResponse(HttpStatusCode.OK, item);
}

public class TestClass
{
    public string Name { get; set; }
    public int Age { get; set; }
}

So, for this scenario use the [KnownTypeAttribute] in the return class (all of them) like this:

[KnownTypeAttribute(typeof(TestClass))]
public class TestClass
{
    public string Name { get; set; }
    public int Age { get; set; }
}

This works for me!

Upvotes: 6

jensendp
jensendp

Reputation: 2135

When it comes to returning data back to the consumer from Web Api (or any other web service for that matter), I highly recommend not passing back entities that come from a database. It is much more reliable and maintainable to use Models in which you have control of what the data looks like and not the database. That way you don't have to mess around with the formatters so much in the WebApiConfig. You can just create a UserModel that has child Models as properties and get rid of the reference loops in the return objects. That makes the serializer much happier.

Also, it isn't necessary to remove formatters or supported media types typically if you are just specifying the "Accepts" header in the request. Playing around with that stuff can sometimes make things more confusing.

Example:

public class UserModel {
    public string Name {get;set;}
    public string Age {get;set;}
    // Other properties here that do not reference another UserModel class.
}

Upvotes: 83

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