.net动态类型在处理json数据方面的应用

我们在.net中处理json数据时，经常需要定义相应的类。比如json数据：{ "name" : "hello", "age" : 18 }，则需要定义相应的类，包含属性 name、age。

如果不想定义那些烦人的类怎么办？这就用到了.net 4.0的动态类型。

1、自定义JavaScriptConverter

 /// <summary>
     /// json转dynamic的转换器
     /// </summary>
     public class JsonDynamicConverter : System.Web.Script.Serialization.JavaScriptConverter
     {
         /// <summary>
         /// 自动定义反序列化
         /// </summary>
         /// <param name="dictionary"></param>
         /// <param name="type"></param>
         /// <param name="serializer"></param>
         /// <returns></returns>
         public override object Deserialize(IDictionary<string, object> dictionary, Type type, System.Web.Script.Serialization.JavaScriptSerializer serializer)
         {
             if (dictionary == null)
                 throw new ArgumentNullException("dictionary");

             if (type == typeof(object))
             {
                 return new JsonDynamicObject(dictionary);
             }

             return null;
         }

         /// <summary>
         /// 序列化
         /// </summary>
         /// <param name="obj"></param>
         /// <param name="serializer"></param>
         /// <returns></returns>
         public override IDictionary<string, object> Serialize(object obj, System.Web.Script.Serialization.JavaScriptSerializer serializer)
         {
             throw new NotImplementedException();
         }

         /// <summary>
         /// 支持的类型
         /// </summary>
         public override IEnumerable<Type> SupportedTypes
         {
             get { return new ReadOnlyCollection<Type>(new List<Type>(new Type[] { typeof(object) })); }
         }
     }

2、定义JsonDynamicObject

 /// <summary>
     /// 代表json的动态对象
     /// </summary>
     public class JsonDynamicObject : System.Dynamic.DynamicObject
     {
         private IDictionary<string, object> dictionary { get; set; }

         /// <summary>
         /// 构造动态json对象
         /// </summary>
         /// <param name="dictionary"></param>
         public JsonDynamicObject(IDictionary<string, object> dictionary)
         {
             this.dictionary = dictionary;
         }

         /// <summary>
         /// 获取成员
         /// </summary>
         /// <param name="binder"></param>
         /// <param name="result"></param>
         /// <returns></returns>
         public override bool TryGetMember(GetMemberBinder binder, out object result)
         {
             if (this.dictionary.ContainsKey(binder.Name) == false)
             {
                 result = null;
                 return true;
             }

             result = this.dictionary[binder.Name];

             if (result is IDictionary<string, object>)
             {
                 result = new JsonDynamicObject(result as IDictionary<string, object>);
             }
             else if (result is ArrayList && (result as ArrayList).Count >  && (result as ArrayList)[] is IDictionary<string, object>)
             {
                 result = new List<dynamic>((result as ArrayList).ToArray().Select(x => new JsonDynamicObject(x as IDictionary<string, object>)));
             }
             else if (result is ArrayList)
             {
                 result = new List<dynamic>((result as ArrayList).ToArray());
             }

             this.dictionary[binder.Name] = result;

             return this.dictionary.ContainsKey(binder.Name);
         }

         /// <summary>
         /// 转换json字符串到dynamic
         /// </summary>
         /// <param name="json"></param>
         /// <returns></returns>
         public static dynamic FromJson(string json)
         {
             var jsSerializer = new System.Web.Script.Serialization.JavaScriptSerializer();
             jsSerializer.RegisterConverters(new[] { new JsonDynamicConverter() });
             return jsSerializer.Deserialize(json, typeof(object));
         }
     }

3、具体用法

 var json = "{ \"name\" : \"hello\", \"age\" : 18 }";
 var person = JsonDynamicObject.FromJson(json);
 Console.WriteLine("name:{0},age:{1}", person.name, person.age);

是不是再也不用定义那些烦人的类了~