Demo using CollectionBase (Set - Get fields in Struct or Object)

using System;
using System.Collections;
using System.Windows.Forms;

namespace WindowsApplication5
{
    public partial class Form1 : Form
    {
        Collection collection1 = new Collection();
        Collection collection2 = new Collection();

        public Form1()
        {
            InitializeComponent();
        }

        private void TurnIn_Click_1(object sender, EventArgs e)
        {
            // them vao collection
            collection1.Add(int.Parse(txtAge.Text), txtName.Text);
            lblStatus.Text = "Test " + txtAge.Text + " added.";
        }

        private void LookAt_Click_1(object sender, EventArgs e)
        {
            bool FirstCheck = collection2.Count() == 0;
            bool bThoat = false;

            while (collection1.Count() > 0 && !bThoat)
            {
                int x = collection1.Count() - 1;
                // copy phan tu cuoi cung cua collection1 thanh phan tu dau tien cua collection2
                collection2.Insert(collection1.GetID(x), collection1.GetName(x), 0);

                // xoa phan tu cuoi cung cua collection1
                collection1.RemoveAt(x);

                // kiem tra phan tu nay co la bai test dang tim
                if (collection2.GetID(0) == int.Parse(txtAge.Text))
                {
                    MessageBox.Show("Student Name is: " + collection2.GetName(0));
                    bThoat = true;
                }
            }

            if (!bThoat) // neu khong tim thay bai test nao
                if (FirstCheck)
                    MessageBox.Show("Test not found.");
                else
                    MessageBox.Show("Please click RETURN A TEST button to reset this result.");
        }        

        private void Return_Click_1(object sender, EventArgs e)
        {
            // chuyen tat ca phan tu cua collection2 vao lai collection1
            while (collection2.Count() > 0)
            {
                collection1.Add(collection2.GetID(0), collection2.GetName(0));
                collection2.RemoveAt(0);
            }
        }     
    }

    public class Collection : CollectionBase
    {
        public struct TuTao
        {
            public int Age;
            public string Name;
        }

        public void Add(int Age, string Name)
        {
            TuTao temp = new TuTao();
            temp.Age = Age;
            temp.Name = Name;
            InnerList.Add(temp);
        }

        public void RemoveAt(int Vitri)
        {
            InnerList.RemoveAt(Vitri);
        }

        public void Insert(int Age, string Name, int Vitri)
        {
            TuTao temp = new TuTao();
            temp.Age = Age;
            temp.Name = Name;
            InnerList.Insert(Vitri, temp);
        }

        public int Count()
        {
            return InnerList.Count;
        }

        public string GetName(int Vitri)
        {
            TuTao temp = (TuTao)InnerList[Vitri];
            return temp.Name;
        }

        public int GetID(int Vitri)
        {
            TuTao temp = (TuTao)InnerList[Vitri];
            return temp.Age;
        }
    }        
}

---

Demo 2

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace CTDL_Chap01_Ex4
{
    class Program
    {
        static void Main(string[] args)
        {
            SinhVien A = new SinhVien();
            A.Add("Le Thanh Dat");
            A.Add("Vo Thuy Lien Tinh");
            A.Add("Nguyen Thi My Hanh");

            SinhVien B = new SinhVien();
            B.Add("http://www.vnxsoft.com");
            B.Add("http://www.microsoft.com");

            Console.WriteLine("Truoc khi swap:");
            for (int i = 0; i < A.Count(); i++)
                Console.WriteLine(A.GetName(i));
            Console.WriteLine();
            for (int i = 0; i < B.Count(); i++)
                Console.WriteLine(B.GetName(i));

            Swap<SinhVien>(ref A, ref B);

            Console.WriteLine("\r\n\r\nSau khi swap:");
            for (int i = 0; i < A.Count(); i++)
                Console.WriteLine(A.GetName(i));
            Console.WriteLine();
            for (int i = 0; i < B.Count(); i++)
                Console.WriteLine(B.GetName(i));

            Console.ReadLine();
        }

        public static void Swap<T>(ref T v1, ref T v2)
        {
            T temp = (T)v1;
            v1 = v2;
            v2 = temp;
        }
    }

    class SinhVien : CollectionBase
    {
        public void Add(object item)
        {
            InnerList.Add(item);
        }

        public string GetName(int Vitri)
        {
            return InnerList[Vitri].ToString();
        }

        public int Count()
        {
            return InnerList.Count;
        }
    }
}