private void cancellButton_Click(object sender, EventArgs e)//取消预约，完成
{
Book book = appointBindingSource.Current as Book;
if (book == null)
{
MessageBox.Show("请选择一本书进行操作！");
return;
}
BookShelfService.CancellAppoint(book, currentClient);
appointBooks = new List <Book>();
appointBindingSource.DataSource = appointBooks;
appointBooks = BookShelfService.GetAllAppointedBooks(currentClient);
appointBindingSource.ResetBindings(false);
appointBindingSource.DataSource = appointBooks;
Books = new List <Book>();
booksBindingSource.DataSource = Books;
Books = BookShelfService.AllBooks();
booksBindingSource.ResetBindings(false);
booksBindingSource.DataSource = Books;
Query(1);
}