c# 虚拟路径转换为绝对路径

 /// <summary>
        /// 解析相对Url
        /// </summary>
        /// <param name="relativeUrl">相对Url</param>
        public static string ResolveUrl(string relativeUrl)
        {
            if (string.IsNullOrWhiteSpace(relativeUrl))
                return string.Empty;
            relativeUrl = relativeUrl.Replace("\", "/");
            if (relativeUrl.StartsWith("/"))
                return relativeUrl;
            if (relativeUrl.Contains("://"))
                return relativeUrl;
            return VirtualPathUtility.ToAbsolute(relativeUrl);
        }