How to export From sql records to data Grid view

Database to Data Grid view:

            string connectionString = null; //connection string

            string sql = null; //query from db

            connectionString = "Data Source=LAB6-168;Initial Catalog=schoolm;User ID=sa;Password=aptech";

            SqlConnection cnn = new SqlConnection(connectionString); //con object

            cnn.Open(); //coneection open form db

            sql = "SELECT * FROM student"; //query

            SqlDataAdapter dscmd = new SqlDataAdapter(sql, cnn); //reads all records from db

            DataSet ds = new DataSet();

            dscmd.Fill(ds);

            dataGridView1.DataSource = ds.Tables[0];