JSON file to a CSV file

This code reads a JSON file named “data.json” using C# and converts it into a DataTable using the Newtonsoft.Json library from NuGet packages. Then it calls the DataTableToCsv() method which takes the DataTable as an argument and returns a string in CSV format. The returned string is then written to a file named “data.csv” using the File.WriteAllText() method.

using System;
using System.IO;
using System.Linq;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Data;

class Program
{
    static void Main()
    {
        // Read the JSON file into a string
        string json = File.ReadAllText("data.json");

        // Convert the JSON string to a JObject
        JObject obj = JsonConvert.DeserializeObject<JObject>(json);

        // Convert the JObject to a DataTable
        DataTable table = JsonToDataTable(obj);

        // Convert the DataTable to a CSV string
        string csv = DataTableToCsv(table);

        // Write the CSV string to a file
        File.WriteAllText("data.csv", csv);
    }

    static DataTable JsonToDataTable(JObject json)
    {
        DataTable table = new DataTable();

        // Get the array of JSON objects
        JArray jsonArray = (JArray)json["data"];

        // Get the column names from the first object
        JObject firstObject = (JObject)jsonArray.First;
        foreach (JProperty prop in firstObject.Properties())
            table.Columns.Add(prop.Name);

        // Add the data rows
        foreach (JObject obj in jsonArray)
        {
            DataRow row = table.NewRow();
            foreach (DataColumn column in table.Columns)
                row[column.ColumnName] = obj[column.ColumnName].ToString();
            table.Rows.Add(row);
        }

        return table;
    }

    static string DataTableToCsv(DataTable table)
    {
        StringBuilder sb = new StringBuilder();

        // Get the column names
        string[] columnNames = table.Columns.Cast<DataColumn>().
                                              Select(column => column.ColumnName).
                                              ToArray();
        sb.AppendLine(string.Join(",", columnNames));

        // Loop through the rows and get the data
        foreach (DataRow row in table.Rows)
        {
            string[] fields = row.ItemArray.Select(field => field.ToString()).
                                            ToArray();
            sb.AppendLine(string.Join(",", fields));
        }

        return sb.ToString();
    }
}