该怎么解决?
private void Form1_Load(object sender, EventArgs e)
        {
           SqlConnection conn = new SqlConnection( "user id=hxh;password=20080712;initial catalog=hxh;server=XINAN0107\\SQLEXPRESS"); 
           conn.Open();
           SqlCommand comm=new SqlCommand("SELECT * FROM Student",conn);
           SqlDataAdapter da = new SqlDataAdapter(comm);
           DataSet ds = new DataSet();
           da.Fill(ds, "Student");
           SqlCommandBuilder cb = new SqlCommandBuilder(da);
           DataTable dt = ds.Tables["Student"];
           
               dt.Rows[1]["age"] = "9";                DataRow row = dt.NewRow();
               row["name"] = "d";
               row["age"] = "21";
               row["course"] = "物理";
               dt.Rows.Add(row);                            textBox1.Text = dt.Rows[3]["name"].ToString();
               textBox2.Text = dt.Rows[3]["age"].ToString();
               textBox3.Text = dt.Rows[3]["course"].ToString();               da.Update(dt);                             }