How to download multiples files with Webforms vb.net inside a loop

Question

I need to download the files using webforms with only one button click but only the first file are downloaded.

How can i do it?

See my code vb code.

---

StrSql = "Select * from TblOS_Anexo"
StrSql = StrSql & " WHERE TblOS_Anexo.IdOS = " & Me.IdOS.Text
StrSql = StrSql & " ORDER By TblOS_Anexo.Seq_Anexo "

Try
    Dim TblOS_Anexo As SqlClient.SqlDataReader = Classes.Class_CriaData_SqlServer.CriaDataReader(Application("Bd_ConnectionString"), StrSql)

    If TblOS_Anexo.HasRows Then
        Do While TblOS_Anexo.Read
            Anexo = TblOS_Anexo("Anexo")
            StrPath = MapPath("~/Anexo_OS/") & Anexo
            TblOS_Anexo("Anexo"))
            If File.Exists(StrPath) Then
                Response.Clear()
                Response.ClearContent()
                Response.ClearHeaders()
                Response.AddHeader("Content-Disposition", "attachment;filename=""" & Anexo & """")
                Response.TransmitFile(Server.MapPath("~/Anexo_OS/" + Anexo))
                Response.Flush()
                Context.ApplicationInstance.CompleteRequest()
                Response.Close()
            End If

        Loop
        Msg.ShowMessage("Download concluded!!!")
    Else
        Msg.ShowMessage("Don't have attachment to download!!!")
    End If
Catch ex As Exception
    Msg.ShowMessage("Error to download the file: " & ex.Message)
End Try

Answer 1

A http request (like file download) can only return one response. Your only option is to zip files into one download file.