using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            listBox1.Items.Add("Sunday");
            listBox1.Items.Add("Monday");
            listBox1.Items.Add("Tuesday");
            listBox1.Items.Add("Wednesday");
            listBox1.Items.Add("Thursday");
            listBox1.Items.Add("Friday");
            listBox1.Items.Add("Saturday");

            listBox1.SelectionMode = SelectionMode.MultiSimple;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            foreach (Object obj in listBox1.SelectedItems )
            {
                MessageBox.Show(obj.ToString ());
            }
        }
    }
}