Inventory.deleteItem C# (CSharp) Method

    public void deleteItem(Item item)
    {
        for (int i = 0; i < ItemsInInventory.Count; i++)
        {
            if (item.Equals(ItemsInInventory[i]))
                ItemsInInventory.RemoveAt(item.indexItemInList);
        }
    }

        private void btnDeleteItem_Click(object sender, System.EventArgs e)
        {
            if (lstInventory.SelectedIndex != -1)             // if something's selected
            {
                var item = lstInventory.SelectedItem as Item; // cast it to an Item

                inventory.deleteItem(item);                   // delete
                updateUI();
            }
        }