private void btnBorrow_Click(object sender, EventArgs e)
 {
     if (_controller.IsAvailable(bookBindingSource.Current as Book))
     {
         using (frmConfirmBorrow frm = new frmConfirmBorrow(bookBindingSource.Current as Book, readerid))
         {
             if (frm.ShowDialog() == DialogResult.OK)
             {
                 _controller.ChangeAvailability(bookBindingSource.Current as Book);
                 bookBindingSource.DataSource = _controller.GetAll();
             }
         }
     }
     else
     {
         MessageBox.Show("Book is not available.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
     }
 }
 private void btnConfirm_Click(object sender, EventArgs e)
 {
     _controller.ChangeAvailability(bookBindingSource.Current as Book);
 }