泛型好难，哪位大侠解释一下下面代码的泛型类

Question

using System;
using System.Collections.Generic;
using System.Text;namespace Ex12_2
{
    class Program
    {
        static void Main(string[] args)
        {
            MyGenericClass<Person> myList = new MyGenericClass<Person>();
            myList.People.Add(new Student("蓝天"));
            myList.People.Add(new Employee("长江"));
            myList.People.Add(new Student("白云"));
            Console.WriteLine("myList EatFood");
            myList.EatFood();
            MyGenericClass<Student> studentList = myList.getStudent();
            Console.WriteLine("\nstudentList EatFood");
            studentList.EatFood();
            MyGenericClass<Person> myList2 = new MyGenericClass<Person>();
            myList2.People.Add(new Employee("黄河"));
            Console.WriteLine("\nmyList2 EatFood");
            myList2.EatFood();
            myList2 = myList2 + studentList;
            Console.WriteLine("\nNew myList2 EatFood");
            myList2.EatFood();
            MyGenericClass<Employee> e = myList.GetSpecies<Employee>();
            e.EatFood();
            Console.ReadKey();
        }
    }
}

Answer 1

using System;
using System.Collections.Generic;
using System.Text;namespace Ex12_2
{
    public abstract class Person
    {
        protected string name;        public string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
            }
        }        public Person()
        {
            name = "Default Name";
        }        public Person(string strName)
        {
            name = strName;
        }
        public void EatFood()
        {
            Console.WriteLine("Person {0} Eat Food.", name);
        }    }}
using System;
using System.Collections.Generic;
using System.Text;namespace Ex12_2
{
    public class Student :Person
    {
        public void Study()
        {
            Console.WriteLine("Student {0} Study.", name);
        }        public Student(string strName)
            : base(strName)
        {
        }
    }}
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;namespace Ex12_2
{
    class MyGenericClass<T> : IEnumerable<T> where T : Person
    {
        private List<T> people;
        public MyGenericClass()
        {
            people = new List<T>();
        }
        public List<T> People
        {
            get { return people; }
        }
        public IEnumerator<T> GetEnumerator()
        {
            return people.GetEnumerator();
        }
        IEnumerator IEnumerable.GetEnumerator()
        {
            return people.GetEnumerator();
        }
        public static implicit operator MyGenericClass<Person>(MyGenericClass<T> Person)
        {
            MyGenericClass<Person> ret = new MyGenericClass<Person>();
            foreach (T t in Person)
                ret.People.Add(t);
            return ret;
        }
        public static MyGenericClass<T> operator +(MyGenericClass<T> p1, MyGenericClass<T> p2)
        {
            MyGenericClass<T> result = new MyGenericClass<T>();
            foreach (T t in p1)
            {
                result.People.Add(t);
            }
            foreach (T t in p2)
            {
                if (!result.People.Contains(t))
                {
                    result.People.Add(t);
                }
            }
            return result;
        }
        public MyGenericClass<Student> getStudent()
        {
            MyGenericClass<Student> ret = new MyGenericClass<Student>();
            foreach(Person t in people)
            {
                if (t is Student)
                    ret.People.Add((Student)t);
            }
            return ret;
        }
        public void EatFood()
        {
            foreach (T t in people)
                t.EatFood();
        }
        public MyGenericClass<U> GetSpecies<U>() where U : T
        {
            MyGenericClass<U> species = new MyGenericClass<U>();
            foreach (T t in people)
            {
                if (t is U)
                {
                    species.People.Add(t as U);
                }
            }
            return species;
        }
    }
}
using System;
using System.Collections.Generic;
using System.Text;namespace Ex12_2
{
    class Employee :Person
    {
        public void doWork()
        {
            Console.WriteLine("Employee {0} is working.", name);
        }        public Employee(string strName) : base(strName)
        {
        }
    }
}
using System;
using System.Collections.Generic;
using System.Text;namespace Ex12_2
{
    class Program
    {
        static void Main(string[] args)
        {
            MyGenericClass<Person> myList = new MyGenericClass<Person>();
            myList.People.Add(new Student("蓝天"));
            myList.People.Add(new Employee("长江"));
            myList.People.Add(new Student("白云"));
            Console.WriteLine("myList EatFood");
            myList.EatFood();
            MyGenericClass<Student> studentList = myList.getStudent();
            Console.WriteLine("\nstudentList EatFood");
            studentList.EatFood();
            MyGenericClass<Person> myList2 = new MyGenericClass<Person>();
            myList2.People.Add(new Employee("黄河"));
            Console.WriteLine("\nmyList2 EatFood");
            myList2.EatFood();
            myList2 = myList2 + studentList;
            Console.WriteLine("\nNew myList2 EatFood");
            myList2.EatFood();
            MyGenericClass<Employee> e = myList.GetSpecies<Employee>();
            e.EatFood();
            Console.ReadKey();
        }
    }
}

Answer 2

   public IEnumerator<T> GetEnumerator()
   {
   return people.GetEnumerator();
   }
   IEnumerator IEnumerable.GetEnumerator()
   {
   return people.GetEnumerator();
   }
   public static implicit operator MyGenericClass<Person>(MyGenericClass<T> Person)
   就是上面几段代码  其实和泛型没什么关系  但是这个是泛型综合的例子