private void DisplayBooksToScreen(List <Book> books) { bunifuCustomTextbox__list_selectedBooks.Text = ""; string printres = ""; foreach (Book bk in books) { printres += "Book ID: " + bk.BookID + " (" + bk.BookName + ")" + Environment.NewLine; UpdateTotalPayment(double.Parse(bk.Price.ToString()) * ParameterManager.GetBookBorrowFeePercentage() / 100); } bunifuCustomTextbox__list_selectedBooks.Text = printres; }