您可以使用.NET做一个HEAD请求，然后看一下响应的状态。

You can use .NET to do a HEAD request and then look at the status of the response.

您code会是这个样子（摘自The卑微的HTTP HEAD请求）：

Your code would look something like this (adapted from The Lowly HTTP HEAD Request):

// create the request
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;

// instruct the server to return headers only
request.Method = "HEAD";

// make the connection
HttpWebResponse response = request.GetResponse() as HttpWebResponse;

// get the status code
HttpStatusCode status = response.StatusCode;

下面是一个清单，详细说明状态codeS 的可以通过状态code枚举返回。

Here's a list detailing the status codes that can be returned by the StatusCode enumerator.