SqlConnection con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings["studentCS"].ConnectionString;

        string name = tb_name.Text;
        string adminno = tb_admno.Text;
        string telephone = tb_telno.Text;
        string height = tb_height.Text;

        string sql = "Update studentTable Set studName=@pStudName, telephone=@pTelephone, heightCM=@pHeightCM";
        sql = sql + " where adminNo= '" + ddl_adminno.SelectedValue + "'";

        SqlCommand cmd = new SqlCommand(sql, con);

        cmd.Parameters.AddWithValue("@pStudName", tb_name.Text);
        cmd.Parameters.AddWithValue("@pAdminNo", tb_admno.Text);
        cmd.Parameters.AddWithValue("@pTelephone", tb_telno.Text);
        cmd.Parameters.AddWithValue("@pHeightCM", tb_height.Text);

        try
        {
            con.Open();
            cmd.ExecuteNonQuery();
            lb_msg.Text = "Record updated successfully";
        }
        catch (Exception ex)
        {
            lb_msg.Text = "Problem encountered:" + ex.Message;
        }
        finally
        {
            con.Close();
            con.Dispose();
            cmd.Dispose();
        }