How to retreive all the properties of an object which is inside another object with C# code?

Question

I have these three tables in SQL Server:

Evaluations (id, textreview, stars, userId, BookId)    
Books      (id, title, ..., userId)    
Users      (id, name, ...)

And I have this code to get data from my tables:

public List<Evaluations> GetAllEvaluationsPerBook()
{
    string sqlCommand = "SELECT DISTINCT b.Title,ev.TextReview,ev.Stars, b.Id " +
                        "FROM[Services.BookDbContext].[dbo].[Evaluations] as ev, " +
                            "[Services.BookDbContext].[dbo].Books as b " +
                        "WHERE b.Id = ev.Book_Id";

    using (var context = new BookDbContext())
    {
        var evaluation = context.Evaluation.SqlQuery(sqlCommand).ToList();

        return evaluation;
    }
}

Now I'm creating a WebApi project in C# with EF6. I use Actions with HttpPost. In one of them I need to retrieve some objects from the DB and send them to a client such as Fiddler in json format. More specifically, I want to get the Title of the Book along with all the Evaluations.

Now I need to create the json below using the code above:

{"id":1,    "textReview":"Good",     "stars":3, "book":null,    "user":null},    
{"id":2,    "textReview":"Awfull",   "stars":1, "book":null,    "user":null},    
{"id":1,    "textReview":"Good",     "stars":3, "book":null,    "user":null},    
{"id":4,    "textReview":"Very Good","stars":4, "book":null,    "user":null}

E.G.: Below you can see the result which I receive from DB, but i cannot make it appear in json format:

How can I do this?

Answer 1

I just found the answer which I wanted:

public List<Evaluations> GetAllEvaluationsPerBook()
    {
        using (var context = new BookDbContext())
        {
            var evaluations = context.Evaluation.ToList();
            var books = context.Book.ToList();
            var users = context.User.ToList();

            return evaluations;
        }
    }

So the code always runs line by line.
The variable evaluations creates a list, filling all its own properties except the Book and the User objects which are remaining null:

{  
   "id":1,
   "textReview":"The Book is good.",
   "stars":3,
   "book":null,
   "user":null
}

After "running" the next line, it fills the list of books. But it fills also the previous list of evaluations with the new list of books:

{  
   "id":1,
   "textReview":"The Book is good.",
   "stars":3,
   "book":{  
      "isbn":1,
      "title":"The Tomb",
      "author":"H. P. Lovecraft",
      "user":null
   },
   "user":null
}

Finally it "runs" the line with the users, (retrieving all the users from the DB and creating a list of users) and automatically it fills the previous Lists, so I have all the information retrieved from the DataBase.