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Is it possible to deserialize JSON into a C# dynamic object?

Problem

Is it possible to convert JSON content to a C# dynamic type? To use the DataContractJsonSerializer, it would be helpful to avoid having to create a number of classes.

Asked by jswanson

Solution #1

You can use the Json class if you don’t mind having a reliance on the System.Web.Helpers assembly:

dynamic data = Json.Decode(json);

It’s bundled with the MVC framework and available as a separate download for the.NET 4 framework. If you find Vlad’s advice useful, please leave him an upvote! If you can’t presume this DLL is present in the client environment, continue reading.

Here is a suggestion for a different deserialization method. I tweaked the code to correct an issue and make it more suited to my coding style. All you’ll need is this code plus a System.Web reference. Extending your project’s scope:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Dynamic;
using System.Linq;
using System.Text;
using System.Web.Script.Serialization;

public sealed class DynamicJsonConverter : JavaScriptConverter
{
    public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
    {
        if (dictionary == null)
            throw new ArgumentNullException("dictionary");

        return type == typeof(object) ? new DynamicJsonObject(dictionary) : null;
    }

    public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
    {
        throw new NotImplementedException();
    }

    public override IEnumerable<Type> SupportedTypes
    {
        get { return new ReadOnlyCollection<Type>(new List<Type>(new[] { typeof(object) })); }
    }

    #region Nested type: DynamicJsonObject

    private sealed class DynamicJsonObject : DynamicObject
    {
        private readonly IDictionary<string, object> _dictionary;

        public DynamicJsonObject(IDictionary<string, object> dictionary)
        {
            if (dictionary == null)
                throw new ArgumentNullException("dictionary");
            _dictionary = dictionary;
        }

        public override string ToString()
        {
            var sb = new StringBuilder("{");
            ToString(sb);
            return sb.ToString();
        }

        private void ToString(StringBuilder sb)
        {
            var firstInDictionary = true;
            foreach (var pair in _dictionary)
            {
                if (!firstInDictionary)
                    sb.Append(",");
                firstInDictionary = false;
                var value = pair.Value;
                var name = pair.Key;
                if (value is string)
                {
                    sb.AppendFormat("{0}:\"{1}\"", name, value);
                }
                else if (value is IDictionary<string, object>)
                {
                    new DynamicJsonObject((IDictionary<string, object>)value).ToString(sb);
                }
                else if (value is ArrayList)
                {
                    sb.Append(name + ":[");
                    var firstInArray = true;
                    foreach (var arrayValue in (ArrayList)value)
                    {
                        if (!firstInArray)
                            sb.Append(",");
                        firstInArray = false;
                        if (arrayValue is IDictionary<string, object>)
                            new DynamicJsonObject((IDictionary<string, object>)arrayValue).ToString(sb);
                        else if (arrayValue is string)
                            sb.AppendFormat("\"{0}\"", arrayValue);
                        else
                            sb.AppendFormat("{0}", arrayValue);

                    }
                    sb.Append("]");
                }
                else
                {
                    sb.AppendFormat("{0}:{1}", name, value);
                }
            }
            sb.Append("}");
        }

        public override bool TryGetMember(GetMemberBinder binder, out object result)
        {
            if (!_dictionary.TryGetValue(binder.Name, out result))
            {
                // return null to avoid exception.  caller can check for null this way...
                result = null;
                return true;
            }

            result = WrapResultObject(result);
            return true;
        }

        public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
        {
            if (indexes.Length == 1 && indexes[0] != null)
            {
                if (!_dictionary.TryGetValue(indexes[0].ToString(), out result))
                {
                    // return null to avoid exception.  caller can check for null this way...
                    result = null;
                    return true;
                }

                result = WrapResultObject(result);
                return true;
            }

            return base.TryGetIndex(binder, indexes, out result);
        }

        private static object WrapResultObject(object result)
        {
            var dictionary = result as IDictionary<string, object>;
            if (dictionary != null)
                return new DynamicJsonObject(dictionary);

            var arrayList = result as ArrayList;
            if (arrayList != null && arrayList.Count > 0)
            {
                return arrayList[0] is IDictionary<string, object> 
                    ? new List<object>(arrayList.Cast<IDictionary<string, object>>().Select(x => new DynamicJsonObject(x))) 
                    : new List<object>(arrayList.Cast<object>());
            }

            return result;
        }
    }

    #endregion
}

You can put it to use in the following way:

string json = ...;

var serializer = new JavaScriptSerializer();
serializer.RegisterConverters(new[] { new DynamicJsonConverter() });

dynamic obj = serializer.Deserialize(json, typeof(object));

Given a JSON string, we can:

{
  "Items":[
    { "Name":"Apple", "Price":12.3 },
    { "Name":"Grape", "Price":3.21 }
  ],
  "Date":"21/11/2010"
}

At runtime, the following code will work:

dynamic data = serializer.Deserialize(json, typeof(object));

data.Date; // "21/11/2010"
data.Items.Count; // 2
data.Items[0].Name; // "Apple"
data.Items[0].Price; // 12.3 (as a decimal)
data.Items[1].Name; // "Grape"
data.Items[1].Price; // 3.21 (as a decimal)

Answered by Drew Noakes

Solution #2

Using Json.NET, it’s quite simple:

dynamic stuff = JsonConvert.DeserializeObject("{ 'Name': 'Jon Smith', 'Address': { 'City': 'New York', 'State': 'NY' }, 'Age': 42 }");

string name = stuff.Name;
string address = stuff.Address.City;

Also using Newtonsoft.Json.Linq:

dynamic stuff = JObject.Parse("{ 'Name': 'Jon Smith', 'Address': { 'City': 'New York', 'State': 'NY' }, 'Age': 42 }");

string name = stuff.Name;
string address = stuff.Address.City;

Documentation: Dynamic JSON Querying

Answered by Tom Peplow

Solution #3

You can do this with the help of System. Web.Helpers. The Decode method of Json returns a dynamic object that you can navigate as needed.

It’s a part of the System. Assemble Web.Helpers (.NET 4.0).

var dynamicObject = Json.Decode(jsonString);

Answered by Vlad Iliescu

Solution #4

This is done with a built-in library in.NET 4.0:

using System.Web.Script.Serialization;
JavaScriptSerializer jss = new JavaScriptSerializer();
var d = jss.Deserialize<dynamic>(str);

This is the most straightforward method.

Answered by Peter Long

Solution #5

Without using a third-party DLL file, you can convert “string JSON data” to an object:

WebClient client = new WebClient();
string getString = client.DownloadString("https://graph.facebook.com/zuck");

JavaScriptSerializer serializer = new JavaScriptSerializer();
dynamic item = serializer.Deserialize<object>(getString);
string name = item["name"];

//note: JavaScriptSerializer in this namespaces
//System.Web.Script.Serialization.JavaScriptSerializer

It’s worth noting that you can also use a custom object.

Personel item = serializer.Deserialize<Personel>(getString);

Answered by İbrahim Özbölük

Post is based on https://stackoverflow.com/questions/3142495/deserialize-json-into-c-sharp-dynamic-object