NameValueCollection To Json 。

原文：http://stackoverflow.com/questions/7003740/how-convert-namevaluecollection-to-json-string

NameValueCollection  转换为 Json 的时候，只把它的Keys 数组 转换为Json ，忽略了 Value ， 方法就是把 NameValueCollection 转换为 字典，再转为Json

自定义Json转换类：

    public static class JsonHelper
    {
        public static string ToJson<T>(this T source)
        {
            if (source == null) return string.Empty;

            var nv = source as NameValueCollection;
            if (nv != null)
            {
                JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
                //执行序列化
                return jsonSerializer.Serialize(nv.ToDictionary());
            }
            else
            {
                JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
                //执行序列化
                return jsonSerializer.Serialize(source);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="str"></param>
        /// <returns></returns>
        public static T FromJson<T>(this string str)
            where T : new()
        {
            if (str.HasValue() == false)
            {
                return new T();
            }
            else
            {
                string ss = str.Trim().Replace(Environment.NewLine, "");
                if (ss.StartsWith("[") == false && ss.StartsWith("{") == false)
                {
                    str = "{" + str + "}";
                }
            }

            if (str[0] == '[')
            {
                JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
                return jsonSerializer.Deserialize<T>(str);
            }
            Type type = typeof(T);
            var nvType = typeof(NameValueCollection);
            if (type == nvType ||
                type.IsSubclassOf(nvType))
            {
                JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
                var dict = jsonSerializer.Deserialize<Dictionary<string, string>>(str);

                NameValueCollection nv = new NameValueCollection();
                if (dict == null) return new T();
                foreach (var item in dict)
                {
                    nv[item.Key] = item.Value;
                }
                return (T)(object)nv;
            }
            else
            {
                JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
                return jsonSerializer.Deserialize<T>(str);
            }
        }

        public static T[] Json2Array<T>(this string str)
        {
            if (str.HasValue() == false)
            {
                return new T[0];
            }
            else
            {
                string ss = str.Trim().Replace(Environment.NewLine, "");
                if (ss.StartsWith("[") == false && ss.StartsWith("{") == false)
                {
                    str = "{" + str + "}";
                }
            }

            JavaScriptSerializer jsonSerializer = new JavaScriptSerializer();
            return jsonSerializer.Deserialize<T[]>(str);
        }
    }