根相对路径转换成当前相对路径

 
 internal static String ResolveClientUrlSimple(string relativeUrl)
  {

   if (relativeUrl == null)
   {
    throw new ArgumentNullException("relativeUrl");
   }
   if (relativeUrl.Length == 0) return relativeUrl;
   if (relativeUrl.StartsWith("~"))
   {
    string text1 = HttpContext.Current.Request.ApplicationPath;
                if (text1.Length == 0)
    {
     return relativeUrl;
                }
                text1 = text1 + relativeUrl.TrimStart('~');
                if (text1.IndexOf("//") > -1)
                    text1 = text1.Replace("//", "/");
    return text1;
   }
   return relativeUrl;
  }