protected override void btnEdit_Click(object sender, EventArgs e)
 {
     if (lvList.SelectedItems.Count > 0)
     {
         var form = new SwitchForm(_instrument);
         form.SwitchItem = lvList.SelectedItems[0].Tag as Item;
         if (DialogResult.OK == form.ShowDialog())
         {
             Item switchItem = form.SwitchItem;
             lvList.SelectedItems[0].Tag = switchItem;
             lvList.SelectedItems[0].SubItems[1].Text = switchItem.name;
             lvList.SelectedItems[0].SubItems[2].Text = switchItem.Description;
         }
     }
 }
 protected override void btnAdd_Click(object sender, EventArgs e)
 {
     var form = new SwitchForm(_instrument);
     if (DialogResult.OK == form.ShowDialog())
     {
         Item switchItem = form.SwitchItem;
         if (switchItem == null)
             switchItem = new Switch();
         AddSwitchItem(switchItem);
     }
 }