我需要一些方法来检查下载文件的大小，而无需下载整个文件。我使用C＃和System.Net.WebClient做检查需要在一个asp.net web服务运行downloads.The。

I need some way to check the size of a download without having to download the entire file. I am using C# and the System.Net.WebClient to do the downloads.The check needs to run in a asp.net webservice.

感谢

推荐答案

使用HTTP方法 HEAD ，以获取的Content-Length：头

Use HTTP method HEAD to retrieve Content-Length: header.

HEAD / HTTP/1.1
Host: www.example.com

HTTP/1.1 200 OK
Date: Wed, 18 Mar 2009 11:21:51 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT
ETag: "b80f4-1b6-80bfd280"
Accept-Ranges: bytes
Content-Length: 438 
Connection: close
Content-Type: text/html; charset=UTF-8