how can i set 2 url support for update..

[standard]

  httpclient = New WebClient
        Dim sourceurl = "http://sample.com/downloa/update.txt" 
        Dim filedir = My.Application.Info.DirectoryPath.ToString & "\" & "update.txt"

        Try
            httpclient.DownloadFileAsync(New Uri(sourceurl), (filedir))


        Catch ex As Exception
            MsgBox("failed update" & ErrorToString(), MsgBoxStyle.Critical)

        End Try