การประเมินการสอนอาจารย์ ตอนแรกผมทำ แค่ ประเมินโดยไม่รู้ว่าเป็นหัวข้ออะไรเก็บแค่คะแนน แบบนี้

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;
using System.Web.Configuration;


public partial class assessment : System.Web.UI.Page
{
    int maxRows = 0;
    private string sqlquery;
    private SqlConnection con;
    private SqlCommand sqlCom;
    private SqlDataAdapter sqlDA;
    private DataSet ds;

    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            //ดูว่า login เข้ามาหรือไม่
            if (Session["stu_id"] == null)
            {
                loading.InnerHtml = "<meta http-equiv='refresh' content='0;URL=login_stu.aspx'>";
            }
            //ดูว่าส่งค่ามาหรือไม่
            if (Request.Params["cid"] == null || Request.Params["year"] == null || Request.Params["term"] == null)
            {
                loading.InnerHtml = "<meta http-equiv='refresh' content='0;URL=home_stu.aspx'>";
            }
            //ต่อฐานข้อมูล
            con = new SqlConnection(WebConfigurationManager.ConnectionStrings["assassment"].ToString());
            //แสดงค่าที่ส่งมา
            setData(Request.Params["cid"]);
            year.Text = Request.Params["year"];
            term.Text = Request.Params["term"];
            
        }
        catch
        {

        }
    }

    private void setData(string cid)
    {
        con.Open();
        sqlquery = "select t.tea_name as 'name',s.sub_id as 'sid',s.sub_name as 'subject' from OPEN_SUBJECT c ";
        sqlquery += "join TEACHER t on c.tea_id = t.tea_id join SUBJECT s on c.sub_id = s.sub_id ";
        sqlquery += "where c.osub_id = '" + cid + "'";
        sqlDA = new SqlDataAdapter(sqlquery, con);
        ds = new DataSet();
        sqlDA.Fill(ds, "osub");
        con.Close();
        if (ds.Tables["osub"].Rows.Count > 0)
        {
            tea_id.Text = ds.Tables["osub"].Rows[0]["name"].ToString();
            sub_id.Text = ds.Tables["osub"].Rows[0]["sid"].ToString();
            sub_name.Text = ds.Tables["osub"].Rows[0]["subject"].ToString();
        }
    }
    protected void btSubmit_Click(object sender, EventArgs e)
    {
        con.Open();
        sqlquery = "select count(*) as 'max' from QUESTION where enabled = 1";
        sqlDA = new SqlDataAdapter(sqlquery, con);
        ds = new DataSet();
        sqlDA.Fill(ds, "co");
        con.Close();
        maxRows = int.Parse(ds.Tables["co"].Rows[0]["max"].ToString());
        int countRD = 0;
        int p5 = 0, p4 = 0, p3 = 0, p2 = 0, p1 = 0;
        for (int i = 0; i < GridView1.Rows.Count; i++)
        {
            GridViewRow gvr = GridView1.Rows[i];
            RadioButton rb5 = (RadioButton)gvr.Cells[0].FindControl("point5");
            RadioButton rb4 = (RadioButton)gvr.Cells[0].FindControl("point4");
            RadioButton rb3 = (RadioButton)gvr.Cells[0].FindControl("point3");
            RadioButton rb2 = (RadioButton)gvr.Cells[0].FindControl("point2");
            RadioButton rb1 = (RadioButton)gvr.Cells[0].FindControl("point1");
            if (rb5.Checked)
            {
                p5++;
                countRD++;
            }
            else if (rb4.Checked)
            {
                p4++;
                countRD++;
            }
            else if (rb3.Checked)
            {
                p3++;
                countRD++;
            }
            else if (rb2.Checked)
            {
                p2++;
                countRD++;
            }
            else if (rb1.Checked)
            {
                p1++;
                countRD++;
            }
        }
        if (countRD < maxRows)
        {
            output.InnerHtml = "กรุณาตอบข้อมูลให้ครบทุกข้อ";
            return;
        }
        con.Open();
        sqlquery = "insert into ASSESSMENT (regis_id,year,term,score5,score4,score3,score2,score1) ";
        sqlquery += "values('" + findRID() + "','" + year.Text + "','" + term.Text + "','" + p5 + "','" + p4 + "','" + p3 + "','" + p2 + "','" + p1 + "')";
        sqlCom = new SqlCommand(sqlquery, con);
        sqlCom.ExecuteNonQuery();
        con.Close();

        //string txt = "";
        //txt += "มากที่สุด : " + p5 + "<br>";
        //txt += "มาก : " + p4 + "<br>";
        //txt += "ปานกลาง : " + p3 + "<br>";
        //txt += "น้อย : " + p2 + "<br>";
        //txt += "ต้องปรับปรุง : " + p1 + "<br>";
        
        loading.InnerHtml = "<meta http-equiv='refresh' content='0;URL=home_stu.aspx'>";
    
    }
    protected void btCancel_Click(object sender, EventArgs e)
    {
        loading.InnerHtml = "<meta http-equiv='refresh' content='0;URL=home_stu.aspx'>";
    }
    private string findRID()
    {     
        sqlquery = "select * from REGISTER where osub_id = '" + Request.Params["cid"].ToString() + "' and stu_id like '" + Session["stu_id"].ToString() + "' and year ='" + year.Text + "'";
        sqlDA = new SqlDataAdapter(sqlquery, con);
        ds = new DataSet();
        sqlDA.Fill(ds, "temp");
        if (ds.Tables["temp"].Rows.Count > 0)
        {
            return ds.Tables["temp"].Rows[0]["regis_id"].ToString();
        }
        else
        {
            return "";
        }
    }
}