判断URL文件是不是在于在。

 

private static bool UrlIsExist(string url){    System.Uri u = null;    try    {        u = new Uri(url);    }    catch { return false; }    bool isExist = false;    System.Net.HttpWebRequest r = System.Net.HttpWebRequest.Create(u) as System.Net.HttpWebRequest;    r.Method = "HEAD";     try    {        System.Net.HttpWebResponse s = r.GetResponse() as System.Net.HttpWebResponse;        if (s.StatusCode == System.Net.HttpStatusCode.OK)        {            isExist = true;        }    }    catch (System.Net.WebException x)    {        try        {            isExist = ((x.Response as System.Net.HttpWebResponse).StatusCode != System.Net.HttpStatusCode.NotFound);        }        catch { isExist = (x.Status == System.Net.WebExceptionStatus.Success); }    }    return isExist;}