C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Serialization;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.Json;

public class Program
{
	public static void Main()
	{
		var exporters = new Dictionary<ExportTypes, IProductsExporter>
        {
            { ExportTypes.Json, new JsonProductsExporter() },
            { ExportTypes.Xml, new XmlProductsExporter() },
            { ExportTypes.Csv, new CsvProductsExporterAdapter(new CsvHelper(';')) }
        };
		
		Console.WriteLine("Please select one:");
		
		Console.WriteLine(
            exporters
                .Select((e, i) => $"{i + 1}. {e.Key}")
                .Aggregate((x, y) => x + Environment.NewLine + y));
		
		var key = Console.ReadLine()!;

        var hasKey = exporters.TryGetValue(Enum.Parse<ExportTypes>(key), out var productExporter);

        if (!hasKey) return;

        var products = new List<Product>
        {
            new()
            {
                Title = "MacBook Pro 14 inch",
                Description = "It's now even more capable, thanks to the new M3 chip."
            },
            new()
            {
                Title = "MacBook Pro 16 inch",
                Description = "It's now even more capable, thanks to the new M3 chip."
            }
        };

        var data = productExporter.Export(products);
        
        Console.WriteLine(data);
	}
}

public class Product
{
    public string Title { get; set; }
    public string Description { get; set; }
}

public interface IProductsExporter
{
    string Export(List<Product> products);
}

public class XmlProductsExporter : IProductsExporter
{
    public string Export(List<Product> products)
    {
        var xmlSerializer = new XmlSerializer(products.GetType());

        using var stringWriter = new StringWriter();
        using var xmlWriter = new XmlTextWriter(stringWriter) { Formatting = Formatting.Indented };
        xmlSerializer.Serialize(xmlWriter, products);

        return stringWriter.ToString();
    }
}

public class JsonProductsExporter : IProductsExporter
{
    public string Export(List<Product> products)
    {
        return JsonSerializer.Serialize(products);
    }
}

public class CsvProductsExporterAdapter : IProductsExporter
{
    private CsvHelper CsvHelper { get; set; }

    public CsvProductsExporterAdapter(CsvHelper csvHelper)
    {
        CsvHelper = csvHelper;
    }

    public string Export(List<Product> data)
    {
        return CsvHelper.GenerateCsv(data.Cast<object>().ToList());
    }
}

public class CsvHelper
{
    private char Delimiter { get; set; }

    public CsvHelper(char delimiter)
    {
        Delimiter = delimiter;
    }

    public string GenerateCsv(List<object> rows)
    {
        if (rows == null) return string.Empty;

        var objectType = rows.FirstOrDefault()!.GetType();
        var headers = objectType.GetProperties().Select(x => x.Name).ToList();

        var stringBuilder = new StringBuilder();
        stringBuilder.AppendLine(string.Join(Delimiter, headers));

        foreach (var row in rows)
        {
            var values = objectType.GetProperties().Select(prop => prop.GetValue(row)).ToList();
            stringBuilder.AppendLine(string.Join(Delimiter, values));
        }

        return stringBuilder.ToString();
    }
}

public enum ExportTypes
{
    Json = 1,
    Xml = 2,
    Csv = 3
}

        using var xmlWriter = new XmlTextWriter(stringWriter) { Formatting = Formatting.Indented };
 
using System;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Serialization;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.Json;
​
public class Program
{
    public static void Main()
    {
        var exporters = new Dictionary<ExportTypes, IProductsExporter>
        {
            { ExportTypes.Json, new JsonProductsExporter() },
            { ExportTypes.Xml, new XmlProductsExporter() },
            { ExportTypes.Csv, new CsvProductsExporterAdapter(new CsvHelper(';')) }
        };
        
        Console.WriteLine("Please select one:");
        
        Console.WriteLine(
            exporters

Cached Result

Please select one:
1. Json
2. Xml
3. Csv