how to get the selected and non-selected values of listview to a button

   const string IN_USE = "in use";
        const string INITIALIZE = "initialize";
        public Form1()
        {
            InitializeComponent();

            bool flag = false;
            for (int i = 0; i < 10; i++)
			{
                ListViewItem lView = new ListViewItem(i.ToString());
                if (flag)
	            {
                    lView.SubItems.Add(IN_USE);
                    listView1.Items.Add(lView);
                    flag = false;
	            }
                else
                {
                    lView.SubItems.Add(INITIALIZE);
                    listView1.Items.Add(lView);
                    flag = true;
                }
			}

            listView1.View = View.Details;
        }

        private void btnInit_Click(object sender, EventArgs e)
        {
            foreach (ListViewItem subItem in listView1.SelectedItems)
            {
                if (subItem.SubItems[1].Text == IN_USE)
                {
                    subItem.SubItems[1].Text = INITIALIZE;
                }
            }
        }

        private void btnInUse_Click(object sender, EventArgs e)
        {
            foreach (ListViewItem subItem in listView1.SelectedItems)
            {
                if (subItem.SubItems[1].Text == INITIALIZE)
                {
                    subItem.SubItems[1].Text = IN_USE;
                }
            }
        }