Net获取当前的URL

private string GetFullUrl()
{
string Url= "http://" + Request.ServerVariables["HTTP_HOST"] + Request.ServerVariables["PATH_INFO"] + "?" + Request.ServerVariables["QUERY_STRING"];
if (Url.EndsWith("?"))

{
Url= Url.Substring(0, Url.Length - 1);
}
return Url;
}