เลือกข้อมูลจาก ddl แล้วไม่เปลี่ยนค่าตามที่เลือก ไป default ที่ค่าแรกเสมอ

Protected Sub ddl_Company_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddl_Company.DataBound
        ddl_Company.Items.Insert(0, "<--- กรุณาเลือกสาขาบริษัท --->")
    End Sub

    Protected Sub ddl_Company_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddl_Company.SelectedIndexChanged
        Dim company_id As Int16 = CShort(ddl_Company.SelectedItem.Value)

        Dim strConn As String
        strConn = WebConfigurationManager.ConnectionStrings("WEBConnectionString").ConnectionString
        Dim Conn As New SqlConnection(strConn)
        Conn.Open()

        Dim strSQL As String
        strSQL = "SELECT company_fullname,company_address,company_tel,company_fax,company_email FROM TB_Mod_Company"
        strSQL &= " where (company_id = @company_id)"

        Dim cmd As New SqlCommand(strSQL, Conn)
        cmd.Parameters.Add("@company_id", SqlDbType.NChar).Value = company_id
        Dim dr As SqlDataReader = cmd.ExecuteReader()
        Dim CompanyDetails, company_fullname, company_address, company_tel, company_fax, company_email As String
        If dr.Read Then
            With dr
                company_fullname = dr.Item("company_fullname").ToString
                company_address = dr.Item("company_address").ToString
                company_tel = dr.Item("company_tel").ToString
                company_fax = dr.Item("company_fax").ToString
                company_email = dr.Item("company_email").ToString
                CompanyDetails = company_fullname + "   " + "ที่อยู่ :" + company_address + " " + "เบอร์โทร :" + company_tel + " " + "เบอร์แฟกซ์ :" + company_fax + " " + "อีเมลล์ : " + company_email
                txt_CompanyDetails.Text = CompanyDetails
            End With

        End If
        Conn.Close()
        Conn = Nothing
    End SubCode (VB.NET)