จะลองทดสอบสร้าง Collection เก็บข้อมูล User แล้ว Input ที่เข้ามาให้ไปตรวจสอบกับข้อมูลใน Collection ยังไงช

class Program
    {
        static void Main(string[] args)
        {         

            viewcustomer vcust = new viewcustomer();
            Console.WriteLine(vcust.getCustomerName(1));
            Console.WriteLine(vcust.getCountCustomer());
            Console.ReadKey();
        }
    }
    public class customer
    {
        public int id { get; set; }
        public string name { get; set; }
    }
    public class viewcustomer
    {
        private IEnumerable<customer> listcustomer = new[] { 
            new customer { id = 1, name = "test1" }
        ,new customer { id = 2, name = "test2" }};
        public string getCustomerName(int id)
        {
            string result = "";
            result = listcustomer.Where(c => c.id == id).FirstOrDefault().name.ToString();
            return result;
        }
        public int getCountCustomer()
        {
            return listcustomer.Count();
        }

    }

public class Customer
{
   public int Id { get; set; }
   public string Name { get; set; }
}

public class CustomerCollection : ObservableCollection<Customer> { }