GUI Windows Form C#

/*
User Interfaces in C#: Windows Forms and Custom Controls
by Matthew MacDonald
Publisher: Apress
ISBN: 1590590457
*/
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
namespace ListBoxObjects
{
    /// 
    /// Summary description for ListBoxObjects.
    /// 

    public class ListBoxObjects : System.Windows.Forms.Form
    {
        internal System.Windows.Forms.CheckedListBox lstCustomers;
        /// 
        /// Required designer variable.
        /// 

        private System.ComponentModel.Container components = null;
        public ListBoxObjects()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();
            //
            // TODO: Add any constructor code after InitializeComponent call
            //
        }
        /// 
        /// Clean up any resources being used.
        /// 

        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null) 
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }
        #region Windows Form Designer generated code
        /// 
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// 

        private void InitializeComponent()
        {
            this.lstCustomers = new System.Windows.Forms.CheckedListBox();
            this.SuspendLayout();
            // 
            // lstCustomers
            // 
            this.lstCustomers.Location = new System.Drawing.Point(8, 8);
            this.lstCustomers.Name = "lstCustomers";
            this.lstCustomers.Size = new System.Drawing.Size(264, 196);
            this.lstCustomers.TabIndex = 2;
            // 
            // ListBoxObjects
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);
            this.ClientSize = new System.Drawing.Size(280, 218);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.lstCustomers});
            this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
            this.Name = "ListBoxObjects";
            this.Text = "ListBox Objects";
            this.Load += new System.EventHandler(this.ListBoxObjects_Load);
            this.ResumeLayout(false);
        }
        #endregion
        /// 
        /// The main entry point for the application.
        /// 

        [STAThread]
        static void Main() 
        {
            Application.Run(new ListBoxObjects());
        }
        private void ListBoxObjects_Load(object sender, System.EventArgs e)
        {
            lstCustomers.Items.Add(new Customer("Maurice", "Respighi", DateTime.Now));
            lstCustomers.Items.Add(new Customer("Sam", "Digweed", DateTime.Now));
            lstCustomers.Items.Add(new Customer("Faria", "Khan", DateTime.Now));
        }
    }
}
public class Customer
{
    public string FirstName;
    public string LastName;
    public DateTime BirthDate;
    
    public Customer()
    {}
    public Customer(string firstName, string lastName, DateTime birthDate)
    {
        this.FirstName = firstName;
        this.LastName = lastName;
        this.BirthDate = birthDate;
    }
    
    public override string ToString()
    {
        return FirstName + " " + LastName;
    }
}