C# - Unexpected character encountered while parsing value: {. Path '[0].Statistics

Question

I am trying to deserialize a JSON object according to my model using the code below:

LoadData<MyModel>(Data.Stats, null);

public void LoadData<TModel>(string data, JsonSerializerSettings jsonSettings) where TModel : class
{
    var mockData = JsonConvert.DeserializeObject<Collection<TModel>>(data, jsonSettings); // ERROR HERE
    Context.SaveChanges();
}

However I am getting an error that reads

Newtonsoft.Json.JsonReaderException: 'Unexpected character encountered while parsing value: {. Path '[0].Statistics', line 7, position 19.'

My JSON object is:

[
  {
    "Id": 3033,
    "Grade": 3,
    "Statistics": { //ERROR OCCURS ON THIS PROPERTY
      "Avatar.Add": 1,
      "TotalPlays": 36,
      "Game.TotalPlays.Spell_Mem_Words": 27,
      "Book.TotalReads.Count": 23,
      "Game.TotalPlays.Count": 39,
      "Character.TotalPlays.L": 23,
      "Character.TotalPlays.E": 3,
      "TotalPlays.Pick_Vocab": 16,
      "Character.TotalPlays.R": 22
    }
  }
]

The Object Model is:

public class MyModel
{
    public int Id { get; set; }
    public int Grade { get; set; }
    public string Statistics { get; set; } 
}

Things I Have Tried

(1) Using json lint I have ensured that the json string is valid.

(2) In javascript serializing the object with back ticks surrounding it works. Backticks don't work in C# JS Fiddle

(3) Tried making the Statistics property in object model to use class called stats instead of string like

public class Stats 
{
    public string Label { get; set;}
    public int Value { get; set; }
}

(4) Tried nearly all the answers on this SO post

Unfortunately I still have not solved this issue. Any ideas?

Solution

I was able to reproduce the problem with this MCVE:

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DeserializeJson
{
    /**
     * REFERENCE:
     * https://stackoverflow.com/questions/53562566/
     *
     * ORIGINAL ERROR:
     * "Unexpected character encountered while parsing value: {. Path '[0].Statistics', line 5, position 19."
     */
     public class Stats
     {
         public string Label { get; set; }
         public int Value { get; set; }
     }

     public class MyModel
     {
         public int Id { get; set; }
         public int Grade { get; set; }
         public string Statistics { get; set; }
     }

    class Program
    {
        static Collection<MyModel> LoadData(string data)
        {
            var retval = JsonConvert.DeserializeObject<Collection<MyModel>>(data);
            return retval;
        }

        static void Main(string[] args)
        {
            try
            {
                string s = File.ReadAllText(@"test-data.json");
                JsonConvert.DefaultSettings = () => new JsonSerializerSettings
                {
                    Formatting = Newtonsoft.Json.Formatting.Indented
                };
                Collection <MyModel> mockData = Program.LoadData(s);
                System.Console.WriteLine("#/items= " + mockData.Count);
                foreach (MyModel item in mockData)
                {
                    System.Console.WriteLine("  id= {0}, Grade={1}, Statistics={2}", item.Id, item.Grade, item.Statistics.ToString());
                }
            }
            catch (Exception ex)
            {
                System.Console.WriteLine("ERROR:", ex);
            }
        }
    }
}

I was able to fix it by:

1. Elaborating your definition of class Stats, then

2. Using Stats in the definition of class MyModel:

   public class Stats
   {
       public int AvatarAdd { get; set; }
       public int TotalPlays { get; set; }
       public int GameTotalPlaysSpellMemWords { get; set; }
       public int BookTotalReadsCount { get; set; }
       public int GameTotalPlaysCount { get; set; }
       public int CharacterTotalPlaysL { get; set; }
       public int CharacterTotalPlaysE { get; set; }
       public int TotalPlaysPick_Vocab { get; set; }
       public int CharacterTotalPlaysR { get; set; }
   }
   
   public class MyModel
   {
       public int Id { get; set; }
       public int Grade { get; set; }
       public Stats Statistics { get; set; }
   }
   

You have several choices (including use the above example verbatim). My suggestion would be to break "Statistics" down into smaller model classes.

Comments

[Flydog57]

When you used the Stats class, how did you declare the Statistics property? Have you considered making Statistics a Dictionary<string, int>?

[gunr2171]

Your Statistics property is a string.

[RyeGuy]

@Flydog57 I will try that. One moment...

[gunr2171]

Also see: Accessing properties with a dot in their name in case you do use a class.

[RyeGuy]

@Flydog57 I receive the error The property 'Statistics' is of type 'Dictionary<string, int>' which is not supported by current database provider. Either change the property CLR type or ignore the property using the '[NotMapped]'

[paulsm4]

I don't see anything "obviously" wrong. An MCVE would definitely be helpful.

[y.luis.rojo]

Possible duplicate of Deserialize JSON object property to string

[RyeGuy]

@paulsm4 how do I make an MCVE for C#? Is there a jsfiddle equivalent for C#?

[RyeGuy]

@y.luis I will try to implement the solution in that answer

[dbc]

@RyeGuy - Is there a jsfiddle equivalent for c#? -- yes there is see dotnetfiddle.net

[Flydog57]

"Not supported by current database provider" What database? I don't see anything database-y in your post.

[Dave]

Changing the Statistics property to Dictionary<string, int> seems to parse the JSON correctly. The error The property 'Statistics' is of type 'Dictionary<string, int>' which is not supported by current database provider. Either change the property CLR type or ignore the property using the '[NotMapped]' seems to be an Entity Framework error which is beyond the original question asked.

[dbc]

Is the set of possible statistics fixed, or variable? If the set of identifiers is fixed, you could simply create a class with the relevant statistics and mark them with [JsonProperty("Avatar.Add")] as shown in this answer to How can I parse a JSON string that would cause illegal C# identifiers?. In fact, one way or another this looks to be a duplicate of that question.

[dbc]

Or you could capture the RAW json as shown in How can I serialize and deserialize a type with a string member that contains “raw” JSON, without escaping the JSON in the process and Deserialize JSON object property to string. Do any of those answers work for you?

[paulsm4]

Q: So, do you know how to "make an MCVE for C#"? It's not just for "asking questions on SO". It's a very powerful debugging/troubleshooting technique that's applicable to ANY kind of problem. Q: Did it help? Is your problem resolved?