How to take duplicates from CSV in C#?

Question

csv

The code is duplicated in the method when reading CSV. How to remove duplicates and why do they occur? Writing to CSV happens without them, but when reading, duplicates start:

using CsvHelper;
using CsvHelper.Configuration;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Net;
using System.Text;
using System.Xml;
 
public class Program
{

    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
 
        public Product(int id, string name)
        {
            Id = id;
            Name = name;
        }
 
    }
 
    public const string PathToDoc = "C:/Users/Saint/Desktop/TaskRetail/yml.xml";
    public static void Main(string[] args)
    {
 
        GetXML();
        Research();
    }
    
    public static void Research()
    {
        Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
 
        var document = new XmlDocument();
        document.Load(PathToDoc);
        var xmlDoc = document.SelectNodes("/yml_catalog/shop/offers/offer");
        var count = xmlDoc.Count;
        var products = new List<Product>();
        Console.WriteLine($"Offers count: {count}");
        for (var i = 0; i < count; i++)
        {
            var element = xmlDoc.Item(i);
            var id = int.Parse(element.Attributes.GetNamedItem("id").Value);
            var name = element.SelectSingleNode("name").InnerText;
            var product = new Product(id, name);
            //Console.WriteLine($"Id: {id}, name: {name}");
 
            products.Add(product);
 
            using (var writer = new StreamWriter("C:\\Users\\Saint\\Desktop\\TaskRetail\\file.csv", false, Encoding.UTF8))
            using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
            {
                csv.WriteRecords(products);
            }
 
            var config = new CsvConfiguration(CultureInfo.InvariantCulture) 
            { 
            PrepareHeaderForMatch = header => header.Header.ToLower()
            };
 
            using (var reader = new StreamReader("C:\\Users\\Saint\\Desktop\\TaskRetail\\file.csv", Encoding.UTF8))
            using (var csv = new CsvReader(reader, config))
 
            {
                var records = csv.GetRecords<Product>();
 
                foreach (var record in records)
                {
                    Console.WriteLine($"{record.Id} {record.Name}");
               }
            }
        }
    }
}

Answer 1

Probably, the reading should be taken out of the cycle, which
for (var i = 0; i < count; i++)