private void button_store_Click(object sender, EventArgs e)
{
string storeString = textBno.Text + '\t' + textCatelogy.Text + '\t' + textTitle.Text + '\t' +
textPress.Text + '\t' + textYear.Text + '\t' + textAuthor.Text + '\t' +
textPrice.Text + '\t' + textTotal.Text;
ldb.AddBook(storeString);
}