Custom methods to convert Json strings to C objects

Here, Atrribute is used to convert the Json string into an C# object. Due to limited functionality, this version is only for Json strings, such as "response":"Hello","id":21231513,"result":100,"msg":"OK "; Instead of the Json array. Here Atrribute is applied to a property, like Atrribute1 in NHibernate, which is reflected at run time to get the property corresponding to which key in the Json string.

namespace JsonMapper
{
    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
    public class JsonFieldAttribute : Attribute
    {
        private string _Name = string.Empty;
        public string Name
        {
            get { return _Name; }
            set { _Name = value; }
        }
    }
}

Next is the core code in the conversion tool, which is mainly to decompose and analyze key and value in the Json string, and obtain and assign the corresponding properties in the object through reflection.

namespace JsonMapper
{
    public class JsonToInstance
    {
        public T ToInstance<T>(string json) where T : new()
        {
            Dictionary<string, string> dic = new Dictionary<string, string>();
            string[] fields = json.Split(',');
            for (int i = 0; i < fields.Length; i++ )
            {
                string[] keyvalue = fields[i].Split(':');
                dic.Add(Filter(keyvalue[0]), Filter(keyvalue[1]));
            }
            PropertyInfo[] properties = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
            T entity = new T();
            foreach (PropertyInfo property in properties)
            {
                object[] propertyAttrs = property.GetCustomAttributes(false);
                for (int i = 0; i < propertyAttrs.Length; i++) 
                {
                    object propertyAttr = propertyAttrs[i];
                    if (propertyAttr is JsonFieldAttribute)
                    {
                        JsonFieldAttribute jsonFieldAttribute = propertyAttr as JsonFieldAttribute;
                        foreach (KeyValuePair<string ,string> item in dic)
                        {
                            if (item.Key == jsonFieldAttribute.Name)
                            {
                                Type t = property.PropertyType;
                                property.SetValue(entity, ToType(t, item.Value), null);
                                break;
                            }
                        }
                    }
                }
            }
            return entity;
        }
        private string Filter(string str)
        {
            if (!(str.StartsWith("\"") && str.EndsWith("\"")))
            {
                return str;
            }
            else 
            {
                return str.Substring(1, str.Length - 2);
            }
        }
        public object ToType(Type type, string value)
        {
            if (type == typeof(string))
            {
                return value;
            }
            MethodInfo parseMethod = null;
            foreach (MethodInfo mi in type.GetMethods(BindingFlags.Static 
                | BindingFlags.Public))
            {
                if (mi.Name == "Parse" && mi.GetParameters().Length == 1)
                {
                    parseMethod = mi;
                    break;
                }
            }
            if (parseMethod == null)
            {
                throw new ArgumentException(string.Format(
                    "Type: {0} has not Parse static method!", type));
            }
            return parseMethod.Invoke(null, new object[] { value });
        }
    }
}

Finally, this is the code for the test

public class Message
    {
        //{ "result": 100, "response": "Who are you?!", "id": 13185569, "msg": "OK." }
        [JsonField(Name = "result")]
        public int Result { get; set; }
        [JsonField(Name = "response")]
        public string Response { get; set; }
        [JsonField(Name = "id")]
        public int Id { get; set; }
        [JsonField(Name = "msg")]
        public string Msg { get; set; }
    }

class Program
    {
        static void Main(string[] args)
        {
            JsonToInstance util = new JsonToInstance();
            string json = "\"response\":\" I'm little yellow chicken in cat sauce \",\"id\":21231513,\"result\":100,\"msg\":\"OK.\"";
            Message m = util.ToInstance<Message>(json);
        }
    }