dyanmically的DropDownList在TextBoxseletedchange相应的列值

dyanmically其seletedchange指数事件中创建的DropDownList没有我写的代码，我想，如果入围任何下拉其correspons价值值将在
来标签或从数据库中的文本框。

DropDownList ddl;

Label la;   global  declared  

for (int i = 0; i < DDLCount; i++)

        {

            // Create the dropdownlists

            ddl = new DropDownList();

            la = new Label();

           

            ddl.ID = "Text" + i;

            la.ID = "la" + i;

 

            ddl.SelectedIndexChanged += new EventHandler(dd1_SelectedIndexChanged);

            //dd2.ID = "Texts" + i;

            LiteralControl l1 = new LiteralControl("<br></br>");

 

            

            SqlConnection con1 = new SqlConnection("Data Source=ABC-0D30299B90A;Initial Catalog=JAPIT;Integrated Security=True");

            con1.Open();

            string st = "select  doe_name from   Doe_detail ";

            SqlCommand cmd = new SqlCommand(st, con1);

            SqlDataReader dr = cmd.ExecuteReader();

            while (dr.Read())

            {

                ddl.Items.Add(dr.GetString(0).ToString());

 



            }

            con1.Close();

  protected void dd1_SelectedIndexChanged(object sender, EventArgs e)

    {

 

        SqlConnection con1 = new SqlConnection("Data Source=ABC-0D30299B90A;Initial Catalog=JAPIT;Integrated Security=True");

        con1.Open();

        string st = "select  doe_id from   Doe_detail  where doe_name=" + ddl.SelectedValue.ToString() + " ";

        SqlCommand cmd = new SqlCommand(st, con1);

        SqlDataReader dr = cmd.ExecuteReader();

        la.Text = dr.GetString(0).ToString();

        la.Text = "seleted";

 

    }

     // Add it to the panel

     Panel3.Controls.Add(ddl);

     Panel3.Controls.Add(la);

     Panel3.Controls.Add(l1);

        }

    }