如何使用c#中的Moodle web服务功能

Question

我有一项任务要从我的c#项目中创建Moodle课程类别，但以下代码总是返回错误响应："单个结构中缺少必需的键：categories"；我的代码如下：

string sitename = "http://localhost/moodle"; 
string token = "0d31f83da49cc21f8dc599fab4b299f0"; 
string url = sitename + "/webservice/rest/server.php?wstoken=" + token + "&wsfunction=core_course_create_categories&moodlewsrestformat=json"; 
category cat = new category(); 
List<category> categories = new List<category>(); 
cat.name = HttpUtility.UrlEncode("2019"); 
cat.parent = int.Parse(HttpUtility.UrlEncode("2")); 
cat.idnumber = HttpUtility.UrlEncode("11"); 
cat.description = HttpUtility.UrlEncode("Academic year 2019"); 
cat.descriptionformat = int.Parse(HttpUtility.UrlEncode("1")); 
cat.theme = HttpUtility.UrlEncode(""); 
categories.Add(cat); 
Dictionary<string, List<category>> param = new Dictionary<string, List<category>>(); 
param.Add("categories", categories.ToList()); 
string jsonList = JsonConvert.SerializeObject(param.ToArray(), Formatting.None); 
var client = new RestClient(url); 
var request = new RestRequest(); 
request.AddHeader("Content-Type", "application/json"); 
request.AddHeader("Accept", "application/json"); 
request.RequestFormat = DataFormat.Json; 
request.AddJsonBody(jsonList); 
request.Method = Method.POST; 
var response = client.Execute(request); 

---

//类别类代码

public class category 
{ 
public string name { get; set; } 
public int parent { get; set; } 
public string idnumber { get; set; } 
public string description { get; set; } 
public int descriptionformat { get; set; } 
public string theme { get; set; } 
public category() 
{ 
descriptionformat = 1; 
theme = ""; 
} 
} 

---

Answer 1

string sitename = "http://localhost/moodle";
string token = "0d31f83da49cc21f8dc599fab4b299f0";  
string url = sitename + "/webservice/rest/server.php?wstoken=" + token +         "&wsfunction=core_course_create_categories&moodlewsrestformat=json";
category cat = new category();
List<category> categories = new List<category>();
cat.name = HttpUtility.UrlEncode("2019");
cat.parent = int.Parse(HttpUtility.UrlEncode("0"));
cat.idnumber = HttpUtility.UrlEncode("11");
cat.description = HttpUtility.UrlEncode("Academic year 2019");
cat.descriptionformat = int.Parse(HttpUtility.UrlEncode("1"));
cat.theme = HttpUtility.UrlEncode(String.Empty);
var client = new RestClient(url);
var request = new RestRequest();
request.AddHeader("Content-Type", "application/json");
request.AddParameter("categories[0][name]", "'" + cat.name + "'", ParameterType.QueryString);
request.AddParameter("categories[0][parent]", cat.parent, ParameterType.QueryString);
request.AddParameter("categories[0][idnumber]", "'" + cat.idnumber + "'", ParameterType.QueryString);
request.AddParameter("categories[0][description]", "'" + cat.description + "'", ParameterType.QueryString);
request.AddParameter("categories[0][descriptionformat]", cat.descriptionformat, ParameterType.QueryString);
request.RequestFormat = DataFormat.Json;
request.Method = Method.POST;
var response = client.Execute(request);