JSON序列化與C#中的資料庫

我需要創建一個從常規列到帶有鍵的 json 的 json。只有我不明白如何在 c# 中做到這一點。我正在使用 Postgresql 資料庫，我需要在那里保存單獨的資料，我需要通過 api 傳遞給服務器，如下所示

我得到的是。

{
  "id": '',
  "title": "",
  "description": "",
  "image": "",
  "question": ""
}

到

{
  "id": {
    "title": "",
    "description": "",
    "image": "",
    "question": ""
  }
}

這是我的代碼

[HttpGet]
public JsonResult Get(int id)
{
    string query =
        @"
        select id as ""id"", 
            title as ""title"",
            description as ""description"",
            image as ""image"",
            question as ""question""
        from card";

    DataTable dt = new DataTable();
    string sqlDataSource =
        _configuration.GetConnectionString("EmployeeAppCon");
    NpgsqlDataReader myReader;
    using (NpgsqlConnection myCon = new NpgsqlConnection(sqlDataSource))
    {
        myCon.Open();
        using (NpgsqlCommand myCommand = new NpgsqlCommand(query, myCon)
        )
        {
            myReader = myCommand.ExecuteReader();
            dt.Load (myReader);
            myReader.Close();
            myCon.Close();
        }
    }
    string temp = JsonConvert.SerializeObject(dt);

    return new JsonResult(dt);
}

uj5u.com熱心網友回復：

添加以下類

public class MyCalss
{
   public MyItem ID { get; set; }
}
public class MyItem
{
   public string Title { get; set; }
   public string Description { get; set; }
   public string Image { get; set; }
   public string Question { get; set; }
}

然后然后將以下行添加到您的代碼中

List<MyCalss> items = new List<MyCalss>();
foreach (DataRow row in dt.Rows)
{
   MyCalss item = new MyCalss();
   item.ID = new MyItem();
   item.ID.Title = row["title"].ToString();
   item.ID.Description = row["description"].ToString();
   item.ID.Image = row["image"].ToString();
   item.ID.Question = row["question"].ToString();
   items.Add(item);
}
string temp = JsonConvert.SerializeObject(items);

uj5u.com熱心網友回復：

根據您提供的資訊，我假設您的查詢回傳多個具有唯一 ID 的記錄。因此，您的最終 json 可能如下所示：

{
  "id1": {
    "title": "",
    "description": "",
    "image": "",
    "question": ""
  },
  ...
  "idn": {
    "title": "",
    "description": "",
    "image": "",
    "question": ""
  }
}

為了有一個這樣的結構，你需要改變你的DataTable進入Dictionary<string, Data>。的Data是自定義的結構來存盤title...question欄位：

struct Data
{
   public string Title;
   public string Description;
   public string Image;
   public string Question;
}

映射可以通過 LINQ 寫成這樣：

var data = (from DataRow row in dt.Rows
            select new KeyValuePair<string, Data>
            (
                row["id"].ToString(),
                new Data
                {
                    Title = row["title"].ToString(),
                    Description = row["description"].ToString(),
                    Image = row["image"].ToString(),
                    Question = row["question"].ToString()
                }
            )).ToDictionary(pair => pair.Key, pair => pair.Value);

最后，您只需要創建一個JsonSerializerSettings來指定輸出應使用駝峰式大小寫：

var camelCasingSettings = new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() };
var json = JsonConvert.SerializeObject(data, camelCasingSettings);

我使用以下資料進行測驗：

var dt = new DataTable();
dt.Columns.Add("id", typeof(string));
dt.Columns.Add("title", typeof(string));
dt.Columns.Add("description", typeof(string));
dt.Columns.Add("image", typeof(string));
dt.Columns.Add("question", typeof(string));

dt.Rows.Add("1", "T1", "D1", "I1", "Q1");
dt.Rows.Add("n", "Tn", "Dn", "In", "Qn");

輸出如下所示：

{
   "1":{
      "title":"T1",
      "description":"D1",
      "image":"I1",
      "question":"Q1"
   },
   "n":{
      "title":"Tn",
      "description":"Dn",
      "image":"In",
      "question":"Qn"
   }
}

標籤：C＃ json PostgreSQL的

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