Add Object to ListBox in C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

public class Form1 : Form
{
     private System.Windows.Forms.ListBox lstCustomers;
     public Form1()
     {
          InitializeComponent();
          lstCustomers.Items.Add(new Customer("A", "B", DateTime.Now.AddDays(-10)));
          lstCustomers.Items.Add(new Customer("C", "D", DateTime.Now.AddDays(-100)));
          lstCustomers.Items.Add(new Customer("F", "G", DateTime.Now.AddDays(-500)));
     }
     private void lstCustomers_SelectedIndexChanged(object sender, EventArgs e)
     {
          Customer cust = (Customer)lstCustomers.SelectedItem;
          MessageBox.Show("Birth Date: " + cust.BirthDate.ToShortDateString());
     }
     private void InitializeComponent()
     {
          this.lstCustomers = new System.Windows.Forms.ListBox();
          this.SuspendLayout();
          //
          // lstCustomers
          //
          this.lstCustomers.FormattingEnabled = true;
          this.lstCustomers.Location = new System.Drawing.Point(12, 12);
          this.lstCustomers.Name = "lstCustomers";
          this.lstCustomers.Size = new System.Drawing.Size(120, 95);
          this.lstCustomers.TabIndex = 0;
          this.lstCustomers.SelectedIndexChanged += new System.EventHandler(this.lstCustomers_SelectedIndexChanged);
          //
          // Form1
          //
          this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
          this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
          this.ClientSize = new System.Drawing.Size(308, 230);
          this.Controls.Add(this.lstCustomers);
          this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
          this.Name = "Form1";
          this.Text = "Form1";
          this.ResumeLayout(false);
     }

     [STAThread]
     static void Main()
     {
          Application.EnableVisualStyles();
          Application.Run(new Form1());
     }
}

public class Customer
{
     public string FirstName;
     public string LastName;
     public DateTime BirthDate;

     public Customer() { }

     public Customer(string firstName, string lastName, DateTime birthDate)
     {
          FirstName = firstName;
          LastName = lastName;
          BirthDate = birthDate;
     }

     public override string ToString()
     {
          return FirstName + " " + LastName;
     }
}