' Open the standard dialog to download a file located on the server' whose virtual path is passed as an argument. This routine is useful when' you want to download a file that is otherwise processed by IIS.  ' This routine must be included in an asp.net page, so that it can access ' the Server and Response objects.Sub DownloadFile(ByVal virtualPath As String)    ' retrieve the physical path of the file to download, and create    ' a FileInfo object to read its properties    Dim FilePath As String = Server.MapPath(virtualPath)    Dim TargetFile As New System.IO.FileInfo(FilePath)      ' clear the current output content from the buffer    Response.Clear()    ' add the header that specifies the default filename for the Download/    ' SaveAs dialog    Response.AddHeader("Content-Disposition", "attachment; filename=" + _        TargetFile.Name)    ' add the header that specifies the file size, so that the browser    ' can show the download progress    Response.AddHeader("Content-Length", TargetFile.Length.ToString())    ' specify that the response is a stream that cannot be read by the    ' client and must be downloaded    Response.ContentType = "application/octet-stream"    ' send the file stream to the client    Response.WriteFile(TargetFile.FullName)    ' stop the execution of this page    Response.End()End Sub