Don't know how to set Web API, problem to retrieve the data

I had this problem few days ago, And thought that I'd found the solution which was
setting lazy loading : false.
but my problem to retrieve the data persisted.
Using fiddler, or a front-end app I can't retrieve the data and as result I have only has values like : $ref=6
I think it is some kind of general setting problem, so I'm going to give some information here.

controller:

    [AllowAnonymous]

    [HttpGet]

    [Route("GetQuestionsByTestId/{id}")]

    public ICollection<Question> GetQuestionsByTestId(int id)

    {

        return db.Questions.Where(t => t.TestId == id)

            .Include(a => a.Answers)

            .Include(q=>q.Test)

            .Include(q=>q.Test.TestType)

            .ToList();

    }

identityModels:

   public ApplicationDbContext()

        : base("DefaultConnection", throwIfV1Schema: false)

    {

        this.Configuration.LazyLoadingEnabled = false; //false for Lazy Loading Off

        this.Configuration.ProxyCreationEnabled = false;

    }

WebApiConfig:

       var json = config.Formatters.JsonFormatter;

        json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;

        config.Formatters.Remove(config.Formatters.XmlFormatter);

question Model:

    [Table("Question")]

    public class Question

     {

    public Question()

    {

        Answers = new HashSet<Answer>();

    }

    [Key]

    public int QuestionId { get; set; }

    [Required]

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; } 

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }



    public virtual ICollection<Answer> Answers { get; set; }





    [ForeignKey("Chapter")]

    public int ChapterId { get; set; }

    public Chapter Chapter { get; set; }





    [ForeignKey("Test")]

    public int TestId { get; set; }

    public Test Test { get; set; }



}

my return retrieved with chrome NETWORK: this is where my problem is:

     [{$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…},…]

     0: {$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…}

     1: {$ref: "6"}

second object is not visible, there is only this: $ref:"6"

Please help, losing hope here.

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

asked Nov 19 '18 at 12:21

James

I suspect that the $ref:"6" is generated to avoid "bidirectional-relations-in-your-source-data" from causing "infinite-loops-caused-by-infinite-nested-objects-in-the-JSON-output".
– Peter B
Nov 19 '18 at 12:25

thank you very much, this is it.
– James
Nov 19 '18 at 12:48

add a comment |

controller:

    [AllowAnonymous]

    [HttpGet]

    [Route("GetQuestionsByTestId/{id}")]

    public ICollection<Question> GetQuestionsByTestId(int id)

    {

        return db.Questions.Where(t => t.TestId == id)

            .Include(a => a.Answers)

            .Include(q=>q.Test)

            .Include(q=>q.Test.TestType)

            .ToList();

    }

identityModels:

   public ApplicationDbContext()

        : base("DefaultConnection", throwIfV1Schema: false)

    {

        this.Configuration.LazyLoadingEnabled = false; //false for Lazy Loading Off

        this.Configuration.ProxyCreationEnabled = false;

    }

WebApiConfig:

       var json = config.Formatters.JsonFormatter;

        json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;

        config.Formatters.Remove(config.Formatters.XmlFormatter);

question Model:

    [Table("Question")]

    public class Question

     {

    public Question()

    {

        Answers = new HashSet<Answer>();

    }

    [Key]

    public int QuestionId { get; set; }

    [Required]

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; } 

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }



    public virtual ICollection<Answer> Answers { get; set; }





    [ForeignKey("Chapter")]

    public int ChapterId { get; set; }

    public Chapter Chapter { get; set; }





    [ForeignKey("Test")]

    public int TestId { get; set; }

    public Test Test { get; set; }



}

my return retrieved with chrome NETWORK: this is where my problem is:

     [{$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…},…]

     0: {$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…}

     1: {$ref: "6"}

second object is not visible, there is only this: $ref:"6"

Please help, losing hope here.

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

asked Nov 19 '18 at 12:21

James

I suspect that the $ref:"6" is generated to avoid "bidirectional-relations-in-your-source-data" from causing "infinite-loops-caused-by-infinite-nested-objects-in-the-JSON-output".
– Peter B
Nov 19 '18 at 12:25

thank you very much, this is it.
– James
Nov 19 '18 at 12:48

add a comment |

controller:

    [AllowAnonymous]

    [HttpGet]

    [Route("GetQuestionsByTestId/{id}")]

    public ICollection<Question> GetQuestionsByTestId(int id)

    {

        return db.Questions.Where(t => t.TestId == id)

            .Include(a => a.Answers)

            .Include(q=>q.Test)

            .Include(q=>q.Test.TestType)

            .ToList();

    }

identityModels:

   public ApplicationDbContext()

        : base("DefaultConnection", throwIfV1Schema: false)

    {

        this.Configuration.LazyLoadingEnabled = false; //false for Lazy Loading Off

        this.Configuration.ProxyCreationEnabled = false;

    }

WebApiConfig:

       var json = config.Formatters.JsonFormatter;

        json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;

        config.Formatters.Remove(config.Formatters.XmlFormatter);

question Model:

    [Table("Question")]

    public class Question

     {

    public Question()

    {

        Answers = new HashSet<Answer>();

    }

    [Key]

    public int QuestionId { get; set; }

    [Required]

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; } 

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }



    public virtual ICollection<Answer> Answers { get; set; }





    [ForeignKey("Chapter")]

    public int ChapterId { get; set; }

    public Chapter Chapter { get; set; }





    [ForeignKey("Test")]

    public int TestId { get; set; }

    public Test Test { get; set; }



}

my return retrieved with chrome NETWORK: this is where my problem is:

     [{$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…},…]

     0: {$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…}

     1: {$ref: "6"}

second object is not visible, there is only this: $ref:"6"

Please help, losing hope here.

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

asked Nov 19 '18 at 12:21

James

controller:

    [AllowAnonymous]

    [HttpGet]

    [Route("GetQuestionsByTestId/{id}")]

    public ICollection<Question> GetQuestionsByTestId(int id)

    {

        return db.Questions.Where(t => t.TestId == id)

            .Include(a => a.Answers)

            .Include(q=>q.Test)

            .Include(q=>q.Test.TestType)

            .ToList();

    }

identityModels:

   public ApplicationDbContext()

        : base("DefaultConnection", throwIfV1Schema: false)

    {

        this.Configuration.LazyLoadingEnabled = false; //false for Lazy Loading Off

        this.Configuration.ProxyCreationEnabled = false;

    }

WebApiConfig:

       var json = config.Formatters.JsonFormatter;

        json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;

        config.Formatters.Remove(config.Formatters.XmlFormatter);

question Model:

    [Table("Question")]

    public class Question

     {

    public Question()

    {

        Answers = new HashSet<Answer>();

    }

    [Key]

    public int QuestionId { get; set; }

    [Required]

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; } 

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }



    public virtual ICollection<Answer> Answers { get; set; }





    [ForeignKey("Chapter")]

    public int ChapterId { get; set; }

    public Chapter Chapter { get; set; }





    [ForeignKey("Test")]

    public int TestId { get; set; }

    public Test Test { get; set; }



}

my return retrieved with chrome NETWORK: this is where my problem is:

     [{$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…},…]

     0: {$id: "1", QuestionId: 5, Name: "11", Comment: null, Difficulty: 0, Repeat: 0, 

     IsLearned: false,…}

     1: {$ref: "6"}

second object is not visible, there is only this: $ref:"6"

Please help, losing hope here.

asp.net-mvc asp.net-web-api

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

asked Nov 19 '18 at 12:21

James

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

asked Nov 19 '18 at 12:21

James

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

edited Nov 20 '18 at 15:24

matt_lethargic

2,02011225

asked Nov 19 '18 at 12:21

James

asked Nov 19 '18 at 12:21

James

asked Nov 19 '18 at 12:21

James

I suspect that the $ref:"6" is generated to avoid "bidirectional-relations-in-your-source-data" from causing "infinite-loops-caused-by-infinite-nested-objects-in-the-JSON-output".
– Peter B
Nov 19 '18 at 12:25

thank you very much, this is it.
– James
Nov 19 '18 at 12:48

add a comment |

I suspect that the $ref:"6" is generated to avoid "bidirectional-relations-in-your-source-data" from causing "infinite-loops-caused-by-infinite-nested-objects-in-the-JSON-output".
– Peter B
Nov 19 '18 at 12:25

thank you very much, this is it.
– James
Nov 19 '18 at 12:48

I suspect that the $ref:"6" is generated to avoid "bidirectional-relations-in-your-source-data" from causing "infinite-loops-caused-by-infinite-nested-objects-in-the-JSON-output".
– Peter B
Nov 19 '18 at 12:25

thank you very much, this is it.
– James
Nov 19 '18 at 12:48

add a comment |

1 Answer
1

active

oldest

votes

I'm guessing here that you're using Entity Framework to store and retrieve data. Realistically you don't want to be returning data/entities straight from your database, you probably want to map your data into a set of classes called Data Transfer Objects (DTO).

You can do this manually or using a tool such as AutoMapper.

Manually you would do something like this

Create a DTO class:

public class QuestionDTO

{

    public int QuestionId { get; set; }

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; }

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }

}

Change controller method:

[AllowAnonymous]

[HttpGet]

[Route("GetQuestionsByTestId/{id}")]

public IHttpActionResult GetQuestionsByTestId(int id)

{

    var questions = db.Questions.Where(t => t.TestId == id)

        .Include(a => a.Answers)

        .Include(q => q.Test)

        .Include(q => q.Test.TestType)

        .ToList();



    var questionDTOs = new List<QuestionDTO>();



    foreach (var question in questions)

    {

        questionDTOs.Add(new QuestionDTO

        {

            QuestionId = question.QuestionId,

            Name = question.Name,

            Comment = question.Comment,

            Difficulty = question.Difficulty,

            Repeat = question.Repeat,

            IsLearned = question.IsLearned,

            QuestionNumber = question.QuestionNumber

        });

    }



    return Ok(questionDTOs);

}

(I have changed the return type so that you can use the Ok method that will return a 200 message or if needed return other status codes such as 400 using BadRequest() etc)

Using DTOs allows you to control exactly what data is returned and you don't have to worry about changing things like Lazy loading or proxy creation

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

add a comment |

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1 Answer
1

active

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1 Answer
1

active

oldest

votes

You can do this manually or using a tool such as AutoMapper.

Manually you would do something like this

Create a DTO class:

public class QuestionDTO

{

    public int QuestionId { get; set; }

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; }

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }

}

Change controller method:

[AllowAnonymous]

[HttpGet]

[Route("GetQuestionsByTestId/{id}")]

public IHttpActionResult GetQuestionsByTestId(int id)

{

    var questions = db.Questions.Where(t => t.TestId == id)

        .Include(a => a.Answers)

        .Include(q => q.Test)

        .Include(q => q.Test.TestType)

        .ToList();



    var questionDTOs = new List<QuestionDTO>();



    foreach (var question in questions)

    {

        questionDTOs.Add(new QuestionDTO

        {

            QuestionId = question.QuestionId,

            Name = question.Name,

            Comment = question.Comment,

            Difficulty = question.Difficulty,

            Repeat = question.Repeat,

            IsLearned = question.IsLearned,

            QuestionNumber = question.QuestionNumber

        });

    }



    return Ok(questionDTOs);

}

(I have changed the return type so that you can use the Ok method that will return a 200 message or if needed return other status codes such as 400 using BadRequest() etc)

Using DTOs allows you to control exactly what data is returned and you don't have to worry about changing things like Lazy loading or proxy creation

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

add a comment |

You can do this manually or using a tool such as AutoMapper.

Manually you would do something like this

Create a DTO class:

public class QuestionDTO

{

    public int QuestionId { get; set; }

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; }

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }

}

Change controller method:

[AllowAnonymous]

[HttpGet]

[Route("GetQuestionsByTestId/{id}")]

public IHttpActionResult GetQuestionsByTestId(int id)

{

    var questions = db.Questions.Where(t => t.TestId == id)

        .Include(a => a.Answers)

        .Include(q => q.Test)

        .Include(q => q.Test.TestType)

        .ToList();



    var questionDTOs = new List<QuestionDTO>();



    foreach (var question in questions)

    {

        questionDTOs.Add(new QuestionDTO

        {

            QuestionId = question.QuestionId,

            Name = question.Name,

            Comment = question.Comment,

            Difficulty = question.Difficulty,

            Repeat = question.Repeat,

            IsLearned = question.IsLearned,

            QuestionNumber = question.QuestionNumber

        });

    }



    return Ok(questionDTOs);

}

(I have changed the return type so that you can use the Ok method that will return a 200 message or if needed return other status codes such as 400 using BadRequest() etc)

Using DTOs allows you to control exactly what data is returned and you don't have to worry about changing things like Lazy loading or proxy creation

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

add a comment |

You can do this manually or using a tool such as AutoMapper.

Manually you would do something like this

Create a DTO class:

public class QuestionDTO

{

    public int QuestionId { get; set; }

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; }

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }

}

Change controller method:

[AllowAnonymous]

[HttpGet]

[Route("GetQuestionsByTestId/{id}")]

public IHttpActionResult GetQuestionsByTestId(int id)

{

    var questions = db.Questions.Where(t => t.TestId == id)

        .Include(a => a.Answers)

        .Include(q => q.Test)

        .Include(q => q.Test.TestType)

        .ToList();



    var questionDTOs = new List<QuestionDTO>();



    foreach (var question in questions)

    {

        questionDTOs.Add(new QuestionDTO

        {

            QuestionId = question.QuestionId,

            Name = question.Name,

            Comment = question.Comment,

            Difficulty = question.Difficulty,

            Repeat = question.Repeat,

            IsLearned = question.IsLearned,

            QuestionNumber = question.QuestionNumber

        });

    }



    return Ok(questionDTOs);

}

(I have changed the return type so that you can use the Ok method that will return a 200 message or if needed return other status codes such as 400 using BadRequest() etc)

Using DTOs allows you to control exactly what data is returned and you don't have to worry about changing things like Lazy loading or proxy creation

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

You can do this manually or using a tool such as AutoMapper.

Manually you would do something like this

Create a DTO class:

public class QuestionDTO

{

    public int QuestionId { get; set; }

    public string Name { get; set; }

    public string Comment { get; set; }



    public int Difficulty { get; set; }

    public byte Repeat { get; set; } // 0 - 255

    public bool IsLearned { get; set; }

    public string QuestionNumber { get; set; }

}

Change controller method:

[AllowAnonymous]

[HttpGet]

[Route("GetQuestionsByTestId/{id}")]

public IHttpActionResult GetQuestionsByTestId(int id)

{

    var questions = db.Questions.Where(t => t.TestId == id)

        .Include(a => a.Answers)

        .Include(q => q.Test)

        .Include(q => q.Test.TestType)

        .ToList();



    var questionDTOs = new List<QuestionDTO>();



    foreach (var question in questions)

    {

        questionDTOs.Add(new QuestionDTO

        {

            QuestionId = question.QuestionId,

            Name = question.Name,

            Comment = question.Comment,

            Difficulty = question.Difficulty,

            Repeat = question.Repeat,

            IsLearned = question.IsLearned,

            QuestionNumber = question.QuestionNumber

        });

    }



    return Ok(questionDTOs);

}

(I have changed the return type so that you can use the Ok method that will return a 200 message or if needed return other status codes such as 400 using BadRequest() etc)

Using DTOs allows you to control exactly what data is returned and you don't have to worry about changing things like Lazy loading or proxy creation

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

answered Nov 20 '18 at 11:48

matt_lethargic

2,02011225

add a comment |

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