For each does not working properly?

Hi Terrance...here is my code behind..

public partial class Attendance_Percentage : System.Web.UI.Page
{
  SqlConnection Con;
  SqlCommand Cmd;
  SqlDataAdapter Sdap;
  protected void Page_Load(object sender, EventArgs e)
  {
  Con = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=studentmgmt;Integrated Security=True");
  if (!IsPostBack)
  {
  ddlbind1();
  DropDownList2.Items.Add("<-Select->");
  DropDownList3.Items.Add("<-Select->");
  }
  }
  protected void Button1_Click(object sender, EventArgs e)
  {
  try
  {
  gv2_bind();
  foreach (GridViewRow row in GridView2.Rows)
  {
  lblmonth.Text = DropDownList3.SelectedItem.Text;
  noofdayspresent();
  noofdaysabsent();
  Label lbname = (Label)row.FindControl("lblname");
  Label lbclass = (Label)row.FindControl("lblclass");
  Label lbsection = (Label)row.FindControl("lblsection");

  totalworkingdays();
  double present = Convert.ToDouble(lblnoofdayspresent.Text);
  double X = 100;
  double totaldays = Convert.ToDouble(lbltotalworkingdays.Text);
  double total = (present * X) / totaldays;
  lblpercentage.Text = Convert.ToString(total) + "%";
 
  Con.Open();
  SqlCommand Cmd2 = new SqlCommand("Insert Into dailyatttot values ('" + lbname.Text + "','" + lbclass.Text + "','" + lbsection.Text + "','" + lblmonth.Text + "','" + lbltotalworkingdays.Text + "','" + lblnoofdayspresent.Text + "','" + lblnoofdaysabsent.Text + "','" + lblpercentage.Text + "')", Con);
  Cmd2.ExecuteNonQuery();
  Con.Close();
  gv1_bind();
 
  }
  }
  catch (Exception Ex)
  {
  Response.Write(Ex.ToString());
  }
  finally
  {
  }
  }
  protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
  {
  DropDownList2.Items.Clear();
  ddlbind2();
  }
  protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
  {
  DropDownList3.Items.Clear();
  ddlbind3();
  }
  public void ddlbind1()
  {
  try
  {
  Con.Open();
  Cmd = new SqlCommand("Select Distinct Class From student",Con);
  SqlDataReader Sdr;
  Sdr = Cmd.ExecuteReader();

  DropDownList1.Items.Add("<-Select->");
  while (Sdr.Read())
  {
  DropDownList1.Items.Add(Sdr["Class"].ToString());
  }
  }
  catch (Exception Ex1)
  {
  Label labelex = new Label();
  labelex.Text = Ex1.ToString();
  }
  finally
  {
  Con.Close();
  }
  }
  public void ddlbind2()
  {
  try
  {
  Con.Open();
  Cmd = new SqlCommand("Select Distinct Section From student",Con);
  SqlDataReader Sdr;
  Sdr = Cmd.ExecuteReader();

  DropDownList2.Items.Add("<-Select->");
  while (Sdr.Read())
  {
  DropDownList2.Items.Add(Sdr["Section"].ToString());
  }
  }
  catch (Exception Ex2)
  {
  Label labelex1 = new Label();
  labelex1.Text = Ex2.ToString();
  }
  finally
  {
  Con.Close();
  }
  }
  public void ddlbind3()
  {
  try
  {
  Con.Open();
  Cmd = new SqlCommand("Select Distinct [Month] From Dailyattendance",Con);
  SqlDataReader Sdr;
  Sdr = Cmd.ExecuteReader();

  DropDownList3.Items.Add("<-Select->");
  while (Sdr.Read())
  {
  DropDownList3.Items.Add(Sdr["Month"].ToString());
  }
  }
  catch (Exception Ex3)
  {
  Label labelex2 = new Label();
  labelex2.Text = Ex3.ToString();
  }
  finally
  {
  Con.Close();
  }
  }
  public void gv1_bind()
  {
  try
  {
  Con.Open();
  Sdap = new SqlDataAdapter("select [Name],Class,Section,[Month],Total_Workingdays,No_ofdaysPresent,No_ofdaysAbsent,Percentage From dailyatttot Where Section='" + DropDownList2.SelectedItem.Text + "'", Con);
  DataSet Ds = new DataSet();
  Sdap.Fill(Ds);
  GridView1.DataSource = Ds;
  GridView1.DataBind();
  }
  catch (Exception Exgv1)
  {
  Label labelgv1 = new Label();
  labelgv1.Text = Exgv1.ToString();
  }
  finally
  {
  Con.Close();
  }
  }
  public void gv2_bind()
  {
  try
  {
  Con.Open();
  Sdap = new SqlDataAdapter("select T_ID,[Name],Class,Section From Dailyattendance Where Class='"+DropDownList1.SelectedItem.Text+"' and Section='"+DropDownList2.SelectedItem.Text+"'", Con);
  DataSet Ds1 = new DataSet();
  Sdap.Fill(Ds1);
  GridView2.DataSource = Ds1;
  GridView2.DataBind();
  }
  catch (Exception Exgv2)
  {
  Label labelgv2 = new Label();
  labelgv2.Text = Exgv2.ToString();
  }
  finally
  {
  Con.Close();
  }
  }
  public void totalworkingdays()
  {
  try
  {
  foreach (GridViewRow row in GridView2.Rows)
  {
  Label lbname = (Label)row.FindControl("lblname");

  Con.Open();
  Sdap = new SqlDataAdapter("Select (count(Month)/2) Totalworkingdays from Dailyattendance Where Month='" + DropDownList3.SelectedItem.Text + "'", Con);
  DataSet ds = new DataSet();
  Sdap.Fill(ds);
  lbltotalworkingdays.Text = ds.Tables[0].Rows[0]["Totalworkingdays"].ToString();
  Con.Close();
  double a = Convert.ToDouble(lbltotalworkingdays.Text);
  //double tot = a / 2;
  lbltotalworkingdays.Text = Convert.ToString(a);
  }
  }
  catch (Exception EXworkdays)
  {
  Label labelwork = new Label();
  labelwork.Text = EXworkdays.ToString();
  }
  finally
  {
  }
  }
  public void noofdayspresent()
  {
  try
  {
  foreach (GridViewRow row in GridView2.Rows)
  {
  Label lbname = (Label)row.FindControl("lblname");

  Con.Open();
  Sdap = new SqlDataAdapter("Select  count(Present) no_of_dayspresent from Dailyattendance where [Name]='" + lbname.Text + "' and Month='" + DropDownList3.SelectedItem.Text + "' and Present='Present' and (Session1='Forenoon' or Session1='Afternoon')", Con);
  DataSet ds = new DataSet();
  Sdap.Fill(ds);
  lblnoofdayspresent.Text = ds.Tables[0].Rows[0]["no_of_dayspresent"].ToString();
  Con.Close();
  double b = Convert.ToDouble(lblnoofdayspresent.Text);
  double tot1 = b / 2;
  lblnoofdayspresent.Text = Convert.ToString(tot1);
  }
  }
  catch (Exception EXpresentdays)
  {
  Label labelpresent = new Label();
  labelpresent.Text = EXpresentdays.ToString();
  }
  finally
  { 
  }
  }
  public void noofdaysabsent()
  {
  try
  {
  foreach (GridViewRow row in GridView2.Rows)
  {
  Label lbname = (Label)row.FindControl("lblname");

  Con.Open();
  Sdap = new SqlDataAdapter("Select  count([Absent]) no_of_dayabsent from Dailyattendance where [Name]='" + lbname.Text + "' and Month='" + DropDownList3.SelectedItem.Text + "' and [Absent]='Absent' and (Session1='Forenoon' or Session1='Afternoon')", Con);
  DataSet ds = new DataSet();
  Sdap.Fill(ds);
  lblnoofdaysabsent.Text = ds.Tables[0].Rows[0]["no_of_dayabsent"].ToString();
  Con.Close();
  double c = Convert.ToDouble(lblnoofdaysabsent.Text);
  double tot2 = c / 2;
  lblnoofdaysabsent.Text = Convert.ToString(tot2);
  }
  }
  catch (Exception EXabsentdays)
  {
  Label labelabsent = new Label();
  labelabsent.Text = EXabsentdays.ToString();
  }
  finally
  {
  }
  }
}