Newtonsoft.Json类库下载：http://json.codeplex.com/

//使用JObject读写字符串
JObject jop = JObject.Parse(loginResult);
string[] values = jop.Properties().Select(item => item.Value.ToString()).ToArray();

//嵌套格式
JObject joc = (JObject)JsonConvert.DeserializeObject(loginResult);
string cookies = joc["data"]["cookies"].ToString();

//数组型数据
JArray ja = (JArray)JsonConvert.DeserializeObject(cookies);
foreach (JToken j in ja)
{

}