Discussion: how to use delegate anonymous methods to perform universal sorting on collections

  • 2020-05-17 06:10:46
  • OfStack

In Demo below I used two sorts
1. Let Employee inherit IComparable interface and realize CompareTo method sorting
2. Define a method that USES Comparison < T > Delegate, sort operations to anonymous methods
After looking at the code below, you know to use Comparison < T > The benefit of delegation?

    class Employee:IComparable
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public static List<Employee> GetEmployees()
        {
            return new List<Employee>()
            {
                new Employee(){Name ="GuoHu",Age =25},
                new Employee(){Name ="LeiHu",Age =23},
                new Employee(){Name ="JunWenLi",Age =24},
                new Employee(){Name ="JinHaoLiu",Age =25},
                new Employee(){Name ="ChengFang",Age =24}
            };
        }
        public int CompareTo(object obj)
        {
            Employee employee = obj as Employee;
            if (employee != null)
            {
                return Name.CompareTo(employee.Name);
            }
            else
            {
                throw new ArgumentException("obj is not Employee");
            }
        }
    }
    class Test
    {
        static void SortAndShowFiles(string title, Comparison<Employee> employeeInfo)
        {
            List<Employee> employee = Employee.GetEmployees();
            employee.Sort(employeeInfo);
            Console.WriteLine(title);
            foreach(Employee e in employee)
            {
                Console.WriteLine("Name:{0},Age:{1}", e.Name, e.Age);
            }
        }
        static void Main()
        {
            List<Employee> employeeInfo = Employee.GetEmployees();
            //Using IComparable sort 
            employeeInfo.Sort();
            employeeInfo.ForEach(e => Console.WriteLine("Name:{0},Age{1}/t", e.Name, e.Age));
            SortAndShowFiles("Sort by name", delegate(Employee e1, Employee e2) { return e1.Name.CompareTo(e2.Name); });
            SortAndShowFiles("Sort by age", delegate(Employee e1, Employee e2) { return e1.Age.CompareTo(e2.Age); });
        }

    }


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