เลือกDropDownList6แล้ว textboxไม่แสดงข้อมูล รบกวนดูให้ด้วยครับติดตรงไหน

  void Namelist()
        {           
            if (con.State == ConnectionState.Closed)
                    con.Open();
          
            cmd.CommandText = "select * from [EmployeeData] where Section='GA&HR'";
            cmd.Connection = con;
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            da.Fill(ds, "EmployeeData");
            con.Close();
            DropDownList6.DataSource = ds.Tables["EmployeeData"];
            DropDownList6.DataTextField = "Name";
            DropDownList6.DataValueField ="EmployeeID";
            DropDownList6.DataBind();
            DropDownList6.Items.Insert(0, "เลือกชื่อพนักงาน");
        }
        protected void DropDownList6_SelectedIndexChanged(object sender, EventArgs e)
        {
            if(!Page.IsPostBack)
            {
            if (con.State == ConnectionState.Closed)
                    con.Open();
            cmd.CommandText = "select * from [EmployeeData] where Name=@pName";
            cmd.Parameters.AddWithValue("@pName",DropDownList6.SelectedValue);
            cmd.Connection = con;
            SqlDataReader rd = cmd.ExecuteReader();         
            while(rd.Read())
            {                
                TextBox15.Text = rd[0].ToString(); 
                TextBox19.Text = rd[2].ToString();   
                TextBox21.Text = rd[3].ToString();                        
            }        
            rd.Close();   
            con.Close();
        }
        }