Json.NET serialize object with root name

Use anonymous class

Shape your model the way you want using anonymous classes:

var root = new 
{ 
    car = new 
    { 
        name = "Ford", 
        owner = "Henry"
    }
};

string json = JsonConvert.SerializeObject(root);

I found an easy way to render this out... simply declare a dynamic object and assign the first item within the dynamic object to be your collection class...This example assumes you're using Newtonsoft.Json

private class YourModelClass
{
    public string firstName { get; set; }
    public string lastName { get; set; }
}

var collection = new List<YourModelClass>();

var collectionWrapper = new {

    myRoot = collection

};

var output = JsonConvert.SerializeObject(collectionWrapper);

What you should end up with is something like this:

{"myRoot":[{"firstName":"John", "lastName": "Citizen"}, {...}]}

You can easily create your own serializer

var car = new Car() { Name = "Ford", Owner = "John Smith" };
string json = Serialize(car);

string Serialize<T>(T o)
{
    var attr = o.GetType().GetCustomAttribute(typeof(JsonObjectAttribute)) as JsonObjectAttribute;

    var jv = JValue.FromObject(o);

    return new JObject(new JProperty(attr.Title, jv)).ToString();
}

Sorry, my english is not that good. But i like to improve the upvoted answers. I think that using Dictionary is more simple and clean.

class Program
    {
        static void Main(string[] args)
        {
            agencia ag1 = new agencia()
            {
                name = "Iquique",
                data = new object[] { new object[] {"Lucas", 20 }, new object[] {"Fernando", 15 } }
            };
            agencia ag2 = new agencia()
            {
                name = "Valparaiso",
                data = new object[] { new object[] { "Rems", 20 }, new object[] { "Perex", 15 } }
            };
            agencia agn = new agencia()
            {
                name = "Santiago",
                data = new object[] { new object[] { "Jhon", 20 }, new object[] { "Karma", 15 } }
            };


            Dictionary<string, agencia> dic = new Dictionary<string, agencia>
            {
                { "Iquique", ag1 },
                { "Valparaiso", ag2 },
                { "Santiago", agn }
            };

            string da = Newtonsoft.Json.JsonConvert.SerializeObject(dic);

            Console.WriteLine(da);
            Console.ReadLine();
        }


    }

    public class agencia
    {
        public string name { get; set; }
        public object[] data { get; set; }
    }

This code generate the following json (This is desired format)

{  
   "Iquique":{  
      "name":"Iquique",
      "data":[  
         [  
            "Lucas",
            20
         ],
         [  
            "Fernando",
            15
         ]
      ]
   },
   "Valparaiso":{  
      "name":"Valparaiso",
      "data":[  
         [  
            "Rems",
            20
         ],
         [  
            "Perex",
            15
         ]
      ]
   },
   "Santiago":{  
      "name":"Santiago",
      "data":[  
         [  
            "Jhon",
            20
         ],
         [  
            "Karma",
            15
         ]
      ]
   }
}

string Json = JsonConvert.SerializeObject(new Car { Name = "Ford", Owner = "John Smith" }, Formatting.None);

for the root element use GlobalConfiguration.

A very simple approach for me is just to create 2 classes.

public class ClassB
{
    public string id{ get; set; }
    public string name{ get; set; }
    public int status { get; set; }
    public DateTime? updated_at { get; set; }
}

public class ClassAList
{
    public IList<ClassB> root_name{ get; set; } 
}

And when you going to do serialization:

var classAList = new ClassAList();
//...
//assign some value
//...
var jsonString = JsonConvert.SerializeObject(classAList)

Lastly, you will see your desired result as the following:

{
  "root_name": [
    {
      "id": "1001",
      "name": "1000001",
      "status": 1010,
      "updated_at": "2016-09-28 16:10:48"
    },
    {
      "id": "1002",
      "name": "1000002",
      "status": 1050,
      "updated_at": "2016-09-28 16:55:55"
    }
  ]
}

Hope this helps!

Well, you can at least tell Json.NET to include the type name: http://www.newtonsoft.com/json/help/html/T_Newtonsoft_Json_TypeNameHandling.htm . Newtonsoft.Json.JsonSerializer jser = new Newtonsoft.Json.JsonSerializer(); jser.TypeNameHandling = TypeNameHandling.Objects;

The type will be included at the beginning in the "$type" property of the object.

This is not exactly what you are looking for, but it was good enough for me when facing a similiar problem.

Writing a custom JsonConverter is another approach mentioned in similar questions. However, due to nature of how JsonConverter is designed, using that approach for this question is tricky, as you need to be careful with the WriteJson implementation to avoid getting into infinite recursion: JSON.Net throws StackOverflowException when using [JsonConvert()].

One possible implementation:

public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
    //JToken t = JToken.FromObject(value); // do not use this! leads to stack overflow
    JsonObjectContract contract = (JsonObjectContract)serializer.ContractResolver.ResolveContract(value.GetType());

    writer.WriteStartObject();
    writer.WritePropertyName(value.GetType().Name);
    writer.WriteStartObject();
    foreach (var property in contract.Properties)
    {
        // this removes any property with null value
        var propertyValue = property.ValueProvider.GetValue(value);
        if (propertyValue == null) continue;

        writer.WritePropertyName(property.PropertyName);
        serializer.Serialize(writer, propertyValue);
        //writer.WriteValue(JsonConvert.SerializeObject(property.ValueProvider.GetValue(value))); // this adds escaped quotes
    }
    writer.WriteEndObject();
    writer.WriteEndObject();
}

I hope this help.

//Sample of Data Contract:

[DataContract(Name="customer")]
internal class Customer {
  [DataMember(Name="email")] internal string Email { get; set; }
  [DataMember(Name="name")] internal string Name { get; set; }
}

//This is an extension method useful for your case:

public static string JsonSerialize<T>(this T o)
{
  MemoryStream jsonStream = new MemoryStream();
  var serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(typeof(T));
  serializer.WriteObject(jsonStream, o);

  var jsonString = System.Text.Encoding.ASCII.GetString(jsonStream.ToArray());

  var props = o.GetType().GetCustomAttributes(false);
  var rootName = string.Empty;
  foreach (var prop in props)
  {
    if (!(prop is DataContractAttribute)) continue;
    rootName = ((DataContractAttribute)prop).Name;
    break;
  }
  jsonStream.Close();
  jsonStream.Dispose();

  if (!string.IsNullOrEmpty(rootName)) jsonString = string.Format("{{ \"{0}\": {1} }}", rootName, jsonString);
  return jsonString;
}

//Sample of usage

var customer = new customer { 
Name="John",
Email="[email protected]"
};
var serializedObject = customer.JsonSerialize();

You can use a dictionary too and even better add a method to the class itself:

public class Car
{
    [Newtonsoft.Json.JsonProperty(PropertyName = "name")]
    public string Name{get;set;}

    [Newtonsoft.Json.JsonProperty(PropertyName = "owner")]
    public string Owner{get;set;}

    public string ToJson(string rootName)
    {            
        var dictionary = new Dictionary<string, Car>
        {
            { rootName, this }
        };

        return JsonConvert.SerializeObject(dictionary);
    }
}

// Use:
var car = new Car()
{ 
    Name = "Ford", 
    Owner = "Henry"
};

car.ToJson("myCar");