private void ToolsForTransactionWindow_OnLoaded(object sender, RoutedEventArgs e)
        {
            _collectionViewSource = this.FindResource("ListView") as CollectionViewSource;
            var toolsList = TransactionType == TransactionType.Rent ? _db.GetToolsForTransaction(TransactionType.Return) : _db.GetToolsForTransaction(TransactionType.Rent);

            if (toolsList.Count == 0)
            {
                switch (TransactionType)
                {
                case TransactionType.Rent:
                    MessageBox.Show("Nie ma nic do wypożyczenia", "Informacja", MessageBoxButton.OK, MessageBoxImage.Information);
                    break;

                case TransactionType.Return:
                    MessageBox.Show("Nie ma nic do zwrotu", "Informacja", MessageBoxButton.OK, MessageBoxImage.Information);
                    break;
                }

                this.Close();
            }

            if (TempList.Any())
            {
                foreach (var tool in TempList)
                {
                    toolsList.Remove(tool);
                }
            }

            this.DataContext = toolsList;
        }