从 C# 的动态列表创建 JSON 对象

Question

I have a list of two dimensions dynamic as follows :

List<dynamic> tableContent = new List<dynamic>();

List<dynamic> rowHeader = new List<dynamic>();
rowHeader.add("First header");
rowHeader.add("Second header");
rowHeader.add("Third header");
tableContent.add(rowHeader);

for (int i = 0; i < 5; i++) {
  List<dynamic> rowContent = new List<dynamic>();
  rowContent.add("1");
  rowContent.add("2");
  rowContent.add("3");
  tableContent.add(rowContent);
}

My tableContent is essentially

"First header", "Second header", "Third header"
"1"           , "2"            , "3"
"1"           , "2"            , "3"
"1"           , "2"            , "3"
"1"           , "2"            , "3"
"1"           , "2"            , "3"

I want to transform it into json as

[{"First header":"1","Second header":"2","Third header":"3"}
, {"First header":"1","Second header":"2","Third header":"3"}
, {"First header":"1","Second header":"2","Third header":"3"}
, {"First header":"1","Second header":"2","Third header":"3"}
, {"First header":"1","Second header":"2","Third header":"3"}]

How do I do this without changing my initial for loop to create my tableContent? (since I also need it for doing something else).

Thank you

Eko

Answer 1

Your tableContent is not essential to your example. Your tableContent right now is a List<List<string>> so it will be serialized as

[["First header","Second header","Third header"],["1","2","3"],["1","2","3"],["1","2","3"],["1","2","3"],["1","2","3"]]

If you need to keep your for loop unchanged, then write your own custom serializer . If you have no need in keeping for loop unchanged, form your data in right way. For an example:

var tableContent = new List<dynamic>();

for (int i = 0; i < 5; i++)
{
    var rowContent = new Dictionary<dynamic, dynamic>();
    rowContent["First header"] = "1";
    rowContent["Second header"] = "2";
    rowContent["Third header"] = "3";
    tableContent.Add(rowContent);
}

Will result as:

[{"First header":"1","Second header":"2","Third header":"3"},{"First header":"1","Second header":"2","Third header":"3"},{"First header":"1","Second header":"2","Third header":"3"},{"First header":"1","Second header":"2","Third header":"3"},{"First header":"1","Second header":"2","Third header":"3"}]

PS if you have no special purposes, you can change your dynamic to strong types:

var tableContent = new List<Dictionary<string, string>>();

for (int i = 0; i < 5; i++)
{
    var rowContent = new Dictionary<string, string>();
    rowContent["First header"] = "1";
    rowContent["Second header"] = "2";
    rowContent["Third header"] = "3";
    tableContent.Add(rowContent);
}

Answer 2

You can use newtonsoft - Json.NET to build (and parse) jsons.

It can be used in various ways, both "manually" and using automatic serialization. See here: Creating JSON .

The code below demonstrates how to use the "manual" approach to build the json in parallel to building your current data structure (like I understood you'd like to do):

using System;
using System.Collections.Generic;
using System.Diagnostics;
using Newtonsoft.Json.Linq;

namespace Test
{
    internal class Program
    {
        static void Main(string[] args)
        {
            List<List<string>> tableContent = new List<List<string>>();
            JArray tableJson = new JArray(); // This will be the table json object we will build 

            string[] headerNames = { "First header", "Second header", "Third header" };

            List<string> rowHeader = new List<string>();
            rowHeader.Add(headerNames[0]);
            rowHeader.Add(headerNames[1]);
            rowHeader.Add(headerNames[2]);
            tableContent.Add(rowHeader);

            for (int i = 0; i < 5; i++)
            {
                List<string> rowContent = new List<string>();
                JObject rowJson = new JObject(); // This will be the json for one row

                string[] rowElements = { "1", "2", "3" };
                Debug.Assert(rowElements.Length == headerNames.Length);
                for (int j = 0; j < rowElements.Length; ++j)
                {
                    rowContent.Add(rowElements[j]);
                    rowJson[headerNames[j]] = rowElements[j];   // Add the element to the row json
                }
                tableContent.Add(rowContent);
                tableJson.Add(rowJson); // Add the row json to the table json
            }

            // Here tableJson contains the required json.
            // Convert to string and print:
            string tableJsonString = tableJson.ToString();
            Console.WriteLine(tableJsonString);
        }
    }
}

Output:

[
  {
    "First header": "1",
    "Second header": "2",
    "Third header": "3"
  },
  {
    "First header": "1",
    "Second header": "2",
    "Third header": "3"
  },
  {
    "First header": "1",
    "Second header": "2",
    "Third header": "3"
  },
  {
    "First header": "1",
    "Second header": "2",
    "Third header": "3"
  },
  {
    "First header": "1",
    "Second header": "2",
    "Third header": "3"
  }
]

Note: I changed the dynamic lists to have concrete types as this is more efficient.