web 请求中.RTF 的错误 Mimetype

Question

当通过 ASP.NET MVC 中的操作上传 .rtf 文件时，mimetype 似乎是错误的（ application/msword而不是application/rtf ）：

foreach (string _file in Request.Files)
                {
                    var fileContent = Request.Files[_file];
                    if (fileContent != null && fileContent.ContentLength > 0)
                    {
                        var stream = fileContent.InputStream;
                        Attachment attachment = new Attachment
                        {
                            File = stream.ToByteArray(),
                            MimeType = fileContent.ContentType,
                            NomeFile = fileContent.FileName,
                            Description = description
                        };
                     }
                }

fileContent 是HttpPostedFileBase类型。