Fix content length of file in Fileuploader

Hi all,
        this is my code for sending mail with 5 attachments.
...........................................
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msgMail.Body = strBody;

        msgMail.Priority = MailPriority.Normal;

        if (txtAttachment.FileName.Trim() != "")
        {
           msgMail.Attachments.Add(new Attachment(txtAttachment.PostedFile.InputStream, txtAttachment.FileName));
        }
        else
        { }
        if (FileUpload1.FileName.Trim() != "")
        {
    &nbs ...