C# 读取json文件

//FinstrID为json文件中的key值

var js = Readjson("FinstrID");

public static string Readjson(string key)
        {
            string jsonfile = "HPVTest.Designer.json";//JSON文件路径

            using (System.IO.StreamReader file = System.IO.File.OpenText(jsonfile))
            {
                using (JsonTextReader reader = new JsonTextReader(file))
                {
                    JObject o = (JObject)JToken.ReadFrom(reader);
                    var value = o[key].ToString();
                    return value;
                }
            }
        }