.net core下载文件

上传的文件是在wwwroot下  通过保存的路径跟文件名称完成下载

public IActionResult DownloadFile()
{
  var filePath = "/UploadDocuments/GET//20190422050301115.docx";
  var fileName = "项目原型.docx";
  FileStream fs = new FileStream(_hostingEnvironment.WebRootPath + filePath, FileMode.OpenOrCreate);
  fs.Close();
  return File(new FileStream(_hostingEnvironment.WebRootPath + filePath, FileMode.Open), "application/octet-stream", fileName);
}