protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection conn = BaseClass.DBCon();

        conn.Open();
        int score = Convert.ToInt32(TextBox1.Text);
        int id    = Convert.ToInt32(GridView1.SelectedValue);

        Homework homework = new Homework();

        homework.Add2(id, score);
        TextBox1.Text = "";
    }