---------HttpContextresponse.WriteFile(FileName)的文件很大，输出很慢，又没有更快的办法。-------------

Dim text1 As String = request1.Url.AbsolutePath
  Dim text2 As String = request1.PhysicalPath
  ...
  ...
           If File.Exists(text2) Then
                response1.ContentType = Me.Ctype(text1)
                response1.WriteFile(text1)
            Else
  ...
  ...
   Private Function [Ctype](ByVal file As String) As String
        Dim text2 As String = file.Remove(0, (file.LastIndexOf(".") + 1))
        Select Case text2
            Case "jpg"
                Return "image/jpeg"
            Case "jpeg"
                Return "image/jpeg"
            Case "gif"
                Return "image/gif"
            Case "mid"
                Return "audio/x-midi"
            Case "midi"
                Return "audio/x-midi"
            Case "mp3"
                Return "audio/x-mpeg"
            Case "ra"
                Return "audio/x-pn-realaudio"
            Case "ram"
                Return "audio/x-pn-realaudio"
            Case "wav"
                Return "audio/x-wav"
            Case "mov"
                Return "video/quicktime"
            Case "avi"
                Return "video/quicktime"
            Case "au"
                Return "audio/basic"
            Case "rar"
                Return "application/rar"
            Case "zip"
                Return "application/zip"
            Case "doc"
                Return "application/msword"
            Case "xls"
                Return "application/msexcel"
            Case "pdf"
                Return "application/pdf"
        End Select
        Return ("application/" & text2)    End Function普通的文件还可以，现在有一个差不多1G的文件输出就很慢，请教有美更好的办法。