你可以在Newtonsoft.Json的帮助下实现这一点。从NuGet安装它，然后:

using Newtonsoft.Json;

dynamic results = JsonConvert.DeserializeObject<dynamic>(YOUR_JSON);

我想在单元测试中以编程的方式完成，我可以把它打出来。

我的解决方案是:

var dict = JsonConvert.DeserializeObject<ExpandoObject>(json) as IDictionary<string, object>;

现在我可以断言

dict.ContainsKey("ExpectedProperty");

我在我的代码中使用这样的代码，它工作得很好

using System.Web.Script.Serialization;
JavaScriptSerializer oJS = new JavaScriptSerializer();
RootObject oRootObject = new RootObject();
oRootObject = oJS.Deserialize<RootObject>(Your JSon String);

我做了一个使用Expando对象的DynamicJsonConverter的新版本。我使用了expando对象，因为我想使用Json.NET将动态序列化回JSON。

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

public static class DynamicJson
{
    public static dynamic Parse(string json)
    {
        JavaScriptSerializer jss = new JavaScriptSerializer();
        jss.RegisterConverters(new JavaScriptConverter[] { new DynamicJsonConverter() });

        dynamic glossaryEntry = jss.Deserialize(json, typeof(object)) as dynamic;
        return glossaryEntry;
    }

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

            var result = ToExpando(dictionary);

            return type == typeof(object) ? result : null;
        }

        private static ExpandoObject ToExpando(IDictionary<string, object> dictionary)
        {
            var result = new ExpandoObject();
            var dic = result as IDictionary<String, object>;

            foreach (var item in dictionary)
            {
                var valueAsDic = item.Value as IDictionary<string, object>;
                if (valueAsDic != null)
                {
                    dic.Add(item.Key, ToExpando(valueAsDic));
                    continue;
                }
                var arrayList = item.Value as ArrayList;
                if (arrayList != null && arrayList.Count > 0)
                {
                    dic.Add(item.Key, ToExpando(arrayList));
                    continue;
                }

                dic.Add(item.Key, item.Value);
            }
            return result;
        }

        private static ArrayList ToExpando(ArrayList obj)
        {
            ArrayList result = new ArrayList();

            foreach (var item in obj)
            {
                var valueAsDic = item as IDictionary<string, object>;
                if (valueAsDic != null)
                {
                    result.Add(ToExpando(valueAsDic));
                    continue;
                }

                var arrayList = item as ArrayList;
                if (arrayList != null && arrayList.Count > 0)
                {
                    result.Add(ToExpando(arrayList));
                    continue;
                }

                result.Add(item);
            }
            return result;
        }

        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) })); }
        }
    }
}

你可以在Newtonsoft.Json的帮助下实现这一点。从NuGet安装它，然后:

using Newtonsoft.Json;

dynamic results = JsonConvert.DeserializeObject<dynamic>(YOUR_JSON);

c#有一个轻量级JSON库，叫做SimpleJson。

它支持。net 3.5+， Silverlight和Windows Phone 7。

它支持。net 4.0的动态

它也可以作为NuGet包安装

Install-Package SimpleJson