How do I convert this JSON file into a custom c# Object

Question

I'm trying to create a way to convert an entire json file into my custom datatype which is called a product

{  
   "unique_image_url_prefixes":[  

 ],
 "products_and_categories":{  
  "Tops/Sweaters":[  
     {  
        "name":"Knit Stripe S/S Raglan Top",
        "id":302418,
        "image_url":"//d17ol771963kd3.cloudfront.net/129807/ca/_9UoFPZi8Zs.jpg",
        "image_url_hi":"//d17ol771963kd3.cloudfront.net/129807/rc/_9UoFPZi8Zs.jpg",
        "price":9900,
        "sale_price":0,
        "new_item":true,
        "position":10,
        "category_name":"Tops/Sweaters",
        "price_euro":11600,
        "sale_price_euro":0
     }
     ], 
  "Shirts":[  
     {  
        "name":"Supreme®/Comme des Garçons SHIRT® Eyes Rayon Shirt",
        "id":302426,
        "image_url":"//d17ol771963kd3.cloudfront.net/132067/ca/9O934PRlIcw.jpg",
        "image_url_hi":"//d17ol771963kd3.cloudfront.net/132067/rc/9O934PRlIcw.jpg",
        "price":25800,
        "sale_price":0,
        "new_item":true,
        "position":3,
        "category_name":"Shirts",
        "price_euro":29800,
        "sale_price_euro":0
     }
     ]
  }
}

This only shows a few parts of the file the entire source is here, PasteBin

So what I'm trying to do is I convert each part of this (It's a product/item)

    {  
    "name":"Knit Stripe S/S Raglan Top",
    "id":302418,
    "image_url":"//d17ol771963kd3.cloudfront.net/129807/ca/_9UoFPZi8Zs.jpg",
    "image_url_hi":"//d17ol771963kd3.cloudfront.net/129807/rc/_9UoFPZi8Zs.jpg",
    "price":9900,
    "sale_price":0,
    "new_item":true,
    "position":10,
    "category_name":"Tops/Sweaters",
    "price_euro":11600,
    "sale_price_euro":0
    }

To my custom datatype called Product

    public Product(string id_p, string name_p, string image_url_p, string category_name_p)
    {
    id = id_p;
    name = name_p;
    image_url = image_url_p;
    category_name = category_name_p;       
    }

Then after that I'm trying to compare each of these values to a value assigned by the user of my program

     List<Product> products = JsonConvert.DeserializeObject<List<Product>>(JsonString);

     if (products == null) return null;
     foreach (var product in products)
     {
          //  ownerform.Log(product.name, 0);
          if (product.category_name == T.item.Category && product.name.ToLower().Contains(T.item.Keyword.ToLower()))
          {
              ownerform.Log(string.Format("Resolved Keyword! Item : {0}", product.name), T.TID);
              return new GetUrlResponse(true, product);
          }

      }

What I'm doing right now does not work and I really can't find what does.

Answer 1

A good way to use JSON in C# is with JSON.NET

you can find API Documentation from JSON.NET - Official site helps you work with it.

this is an example of converting an entire JSON file into your custom datatype... for example: user this is just an easy example for you to understand better the solution.

{ "user" : { "name" : "asdf", "teamname" : "b", "email" : "c" } }

so the c# would looks like:

public class User
{
    public User(string json)
    {
        JObject jObject = JObject.Parse(json);
        JToken jUser = jObject["user"];
        name = (string) jUser["name"];
        teamname = (string) jUser["teamname"];
        email = (string) jUser["email"];
    }

    public string name { get; set; }
    public string teamname { get; set; }
    public string email { get; set; }
}

// Use
private void Run()
{
    string json = @"{""user"":{""name"":""asdf"",""teamname"":""b"",""email"":""c""}";
    User user = new User(json);

    Console.WriteLine("Name : " + user.name);
    Console.WriteLine("Teamname : " + user.teamname);
    Console.WriteLine("Email : " + user.email);

 }

Answer 2

The exception you got indicates that there's something wrong with your deserialization.

I can't tell what you actually did, but if you tried to deserialize the whole json object (ie, the whole file), you should understand that it doesn't contain a list of Products, but a more complex types' hierarchy. Thus, this line fails:

List<Product> products = JsonConvert.DeserializeObject<List<Product>>(JsonString);

I'll list two options to get things to work for you, choose whatever you feel more comfortable with.

Note that I'll use a more concise json object. In addition, I've added another object to each of the arrays, to make things more realistic (as in your file)):

{
  "unique_image_url_prefixes": [],
  "products_and_categories": {
    "Tops": [
      {
        "name": "Top1",
        "id": "1"
      },
      {
        "name": "Top2",
        "id": "2"
      }
    ],
    "Shirts": [
      {
        "name": "Shirt1",
        "id": "3"
      },
      {
        "name": "Shirt2",
        "id": "4"
      }
    ]
  }
}

Option #1

Build The Class Hierarchy

Go to the post @CodingYoshi linked to, and create the class hierarchy with Visual Studio. You'll get something very similar the following hierarchy, though I'll make it more concise:

public class Rootobject
{
    public object[] unique_image_url_prefixes { get; set; }
     public Products_And_Categories products_and_categories { get; set; }
}

public class Products_And_Categories
{
    public TopsSweaters[] TopsSweaters { get; set; }
    public Shirts[] Shirts { get; set; }
}

public class TopsSweaters
{
    public string name { get; set; }
    public int id { get; set; }
}

public class Shirts
{
    public string name { get; set; }
    public int id { get; set; }
}

Deserialization

This is how you deserialize your string:

string JsonString = @"{""unique_image_url_prefixes"":[],""products_and_categories"":{""TopsSweaters"":[{""name"":""Top1"",""id"":""1""},{""name"":""Top2"",""id"":""2""}],""Shirts"":[{""name"":""Shirt1"",""id"":""3""},{""name"":""Shirt2"",""id"":""4""}]}}"; 
Rootobject container = JsonConvert.DeserializeObject<Rootobject>(JsonString);

You can then iterate over each array ( TopsSweaters , Shirts ) within container.products_and_categories .

Option #2

If you'd like to use some other class hierarchy (eg, your Product class), you can do the following:

Build The Class Hierarchy

public class Product
{
    [JsonProperty("name")]
    public string name { get; set; }

    [JsonProperty("id")]
    public int id { get; set; }
}

// Choose either one of the following (they function the same):    
public class ProductsContainer1
{
    [JsonProperty("TopsSweaters")]
    public List<Product> ProductsList1 { get; set;}

    [JsonProperty("Shirts")]
    public List<Product> ProductsList2 { get; set;}
}

public class ProductsContainer2
{
    public List<Product> TopsSweaters { get; set; }
    public List<Product> Shirts { get; set; }
}

// Choose either one of the following (they function the same): 
public class Things1
{
    [JsonProperty("unique_image_url_prefixes")]
    public object[] Prefixes { get; set;}

    [JsonProperty("products_and_categories")]
    public ProductsContainer1 Products { get; set;}
}

public class Things2
{
    public object[] unique_image_url_prefixes { get; set;}
    public ProductsContainer2 products_and_categories { get; set;}
}

Deserialization

Deserialize as follows:

string JsonString = @"{""unique_image_url_prefixes"":[],""products_and_categories"":{""TopsSweaters"":[{""name"":""Top1"",""id"":""1""},{""name"":""Top2"",""id"":""2""}],""Shirts"":[{""name"":""Shirt1"",""id"":""3""},{""name"":""Shirt2"",""id"":""4""}]}}"; 
// Use either one of the following: 
Things1 container1 = JsonConvert.DeserializeObject<Things1>(JsonString);
Things2 container2 = JsonConvert.DeserializeObject<Things2>(JsonString);