C#修改json文件中的某些值

using Newtonsoft.Json;

JsonSerializer serialiser = new JsonSerializer();
string newContent = string.Empty;
                        using (StreamReader reader = new StreamReader(file.FullName))
                        {
                            string json = reader.ReadToEnd();

                            dynamic jsonObj = JsonConvert.DeserializeObject(json);
                            jsonObj["course/course"]["tabs"][0]["name"] = "Courseware";
jsonObj["course/course"]["tabs"][0]["type"] = "courseware";

                            jsonObj["course/course"]["tabs"][1]["name"] = "Course Info";
                            jsonObj["course/course"]["tabs"][1]["type"] = "course_info";
                            if (jsonObj["course/course"]["lti_passports"] != null)
                            {
                                for (int i = 0; i < jsonObj["course/course"]["lti_passports"].Count; i++)
                                {
                                    string value = jsonObj["course/course"]["lti_passports"][i].ToString();
                                    if (value.Contains("xtreme"))
                                    {
                                        jsonObj["course/course"]["lti_passports"][i] = "test:LeX:test";
                                    }
                                }
                            }

                            for(int i =0; i< jsonObj["course/course"]["advanced_modules"].Count; i++)
                            {
                                AdvancedModules.Add(jsonObj["course/course"]["advanced_modules"][i].ToString());
                            }
                            jsonObj["course/course"]["catalog_visibility"] = "none";

                            newContent = JsonConvert.SerializeObject(jsonObj, Newtonsoft.Json.Formatting.Indented);