private void btnDeleteBook_Click(object sender, EventArgs e) { if (dgvBooks.SelectedRows.Count > 0) { string isbn = dgvBooks.CurrentRow.Cells["book_isbn"].Value.ToString(); if (MessageBox.Show("Do you really want to delete these data?", "Alert", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) == DialogResult.Yes) { string result = bookControl.deleteDataControl(isbn); if (result.Equals("sucess")) { MessageBox.Show("Delete data has been sucessed!"); showBooksInDataGrid(); } else { MessageBox.Show("Delete data it was possible!"); } } } }