C# SqlConnection连接sql server

 try
            {
                SqlConnection conn = new SqlConnection();
                conn.ConnectionString = "Data Source=127.0.0.1;Initial Catalog=123;User ID=sa;Password=123456";
                conn.Open();

                string sql = "SELECT  * FROM table";
                SqlDataAdapter myda = new SqlDataAdapter(sql, conn);
                DataTable dt = new DataTable();
                myda.Fill(dt);
                dataGridView1.DataSource = dt;
                conn.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("错误消息：" + ex.Message, "出现错误");
            }