private void buttonDelete_Click(object sender, RoutedEventArgs e)
        {
            var inventoryItem = (Inventory) dataGridInventory.SelectedItem;
            var item = new Guid(inventoryItem.Id.ToString());

            var nhi = new NHibernateInventory();
            if (nhi.DeleteInventoryItem(item))
            {
                dataGridInventory.ItemsSource = null;
                PopulateDataGrid();
                labelMessage.Content = "Item deleted.";
            }
            else
                labelMessage.Content = "Item deletion failed.";
        }
        /// <summary>
        /// Click event for the delete button.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void deleteInventoryButton_Click(object sender, RoutedEventArgs e)
        {
            Inventory inventoryItem = (Inventory) inventoryDataGrid.SelectedItem;
            Guid itemId = inventoryItem.Id;

            NHibernateInventory nhi = new NHibernateInventory();
            if (nhi.DeleteInventoryItem(itemId))
            {
                inventoryDataGrid.ItemsSource = null;

                // now we need to reload the grid.
                this.LoadInventoryGrid();

                messagelabel.Content = "Item deleted.";
            }
            else
            {
                messagelabel.Content = "Item deletion failed.";
            }
        }