SqlCommand cmd1 = new SqlCommand("select * from hbet_info where id='"+textBox1.Text+"'", con);
=> Is the id field an integer one ?
If so, you should NOT put its value between quotes.
Moreover, it is a very very bad habit to construct sql requests with string concatenations.
SqlCommand cmd1 = new SqlCommand("select * from hbet_info where id=@id", con);