using CsvHelper;
using System;
using System.Collections.Generic;
using System.IO;

namespace Временной2
{
    class Program
    {
        public class DataСoordinate
        {
            public Int32 X { get; set; }
            public Int32 Y { get; set; }
        }

        static void Main(string[] args)
        {
            List<DataСoordinate> dataСoordinates = new List<DataСoordinate>();

            DataСoordinate dc = new DataСoordinate();
            dataСoordinates.Add(new DataСoordinate {X = 10, Y = 20});
            dataСoordinates.Add(new DataСoordinate {X = 20, Y = 40});
            dataСoordinates.Add(new DataСoordinate {X = 30, Y = 50});
            dataСoordinates.Add(new DataСoordinate {X = 40, Y = 80});

            string pathCsvFile = "C:\\Users\\Acer\\Desktop\\test.csv";

            using (StreamWriter streamReader = new StreamWriter(pathCsvFile))
            {
                using (CsvWriter csvReader = new CsvWriter(streamReader))
                {                    
                    csvReader.Configuration.Delimiter = ",";                    
                    csvReader.WriteRecords(dataСoordinates);
                }
            }
        }
    }
}

using CsvHelper;
using System;
using System.Collections.Generic;
using System.IO;

namespace Временной2
{
    class Program
    {
        public struct DataСoordinate
        {
            public Int32 X;
            public Int32 Y;

            public DataСoordinate(Int32 x, Int32 y) {
                X = x;
                Y = y;
            }
        }

        static void Main(string[] args)
        {
            List<DataСoordinate> dataСoordinates = new List<DataСoordinate>();           
            dataСoordinates.Add(new DataСoordinate(10, 20));
            dataСoordinates.Add(new DataСoordinate(20, 40));
            dataСoordinates.Add(new DataСoordinate(30, 50));
            dataСoordinates.Add(new DataСoordinate(40, 80));            

            string pathCsvFile = "C:\\Users\\Acer\\Desktop\\test.csv";
            using (StreamWriter streamReader = new StreamWriter(pathCsvFile))
            {
                using (CsvWriter csvReader = new CsvWriter(streamReader))
                {
                    csvReader.Configuration.Delimiter = ",";
                    csvReader.WriteRecords(dataСoordinates); //Ошибка
                }
            }
        }
    }
}