C#判断远程文件是否存在

//引用System.Net
using system.net

try
{
HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create("http://www.qujingwang.com/defaulti.aspx");
myReq.Method = "HEAD";
HttpWebResponse myRes = (HttpWebResponse)myReq.GetResponse();
if(myRes.StatusCode == HttpStatusCode.OK) //判断如果文件存在，执行以下语句
{
pnl.Visible = true;
pnl1.Visible = false;
}
}
catch //如果远程文件defaulti.asp 不存在，执行以下语句
{
pnl.Visible = false;
pnl1.Visible = true;
}