How to check if a file on the internet still exists?

private static bool FileExists(string url)
{
    bool b = true;


    try
    {
        WebClient wc = new WebClient();
        wc.OpenRead(url);
    }
    catch (WebException ex)
    {
        //(ex.Response as HttpWebResponse).StatusCode == HttpStatusCode.NotFound)
        b = false;
    }
    return b;
}