private void btnNew_Click(object sender, EventArgs e)
    {
        frmToDoDetails frm = new frmToDoDetails();

        if (frm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {
            string[]     arr = new string[2];
            ListViewItem itm;
            arr[0] = frm.TaskTitle;
            arr[1] = frm.Description;
            itm    = new ListViewItem(arr);
            listView1.Items.Add(itm);
        }
    }
    private void listView1_DoubleClick(object sender, EventArgs e)
    {
        ListViewItem   currentItem = listView1.SelectedItems[0];
        frmToDoDetails frm         = new frmToDoDetails();

        frm.TaskTitle   = currentItem.SubItems[0].Text;
        frm.Description = currentItem.SubItems[1].Text;
        frm.EditMode    = true;
        if (frm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {
            currentItem.SubItems[0].Text = frm.TaskTitle;
            currentItem.SubItems[1].Text = frm.Description;
        }
    }