using System;

using System.Collections.Generic;

using System.Linq;

​

public class ManufacturerInfo

{

    public string Name { get; set; }

​

    public string Url { get; set; }

}

​

public class Program

{

    public static void Main()

    {

        var manufacturers = new List<ManufacturerInfo>{

            new ManufacturerInfo{Name = "Garmin", Url = "http://www.google.com/0"},

            new ManufacturerInfo{Name = "Nike", Url = "http://www.google.com/1"}, 

            new ManufacturerInfo{Name = "New Balance", Url = "http://www.google.com/2"}, 

            new ManufacturerInfo{Name = "Reebok", Url = "http://www.google.com/3"}, 

            new ManufacturerInfo{Name = "Under armour", Url = "http://www.google.com/4"}, 

            new ManufacturerInfo{Name = "xiaomi", Url = "http://www.google.com/5"}, 

            new ManufacturerInfo{Name = "", Url = "http://www.google.com/fault1"}, 

            new ManufacturerInfo{Name = null, Url = "http://www.google.com/fault2"}, 

        };

        foreach (var charGroup in manufacturers.OrderBy(man => man.Name).GroupBy(man => man.Name?.ToUpperInvariant().FirstOrDefault()))

        {

            Console.WriteLine(charGroup.Key);

            foreach (var manufacturer in charGroup)

            {

                Console.WriteLine($"{manufacturer.Name} - {manufacturer.Url}");

            }

        }

    }

}