Resolve URL functions

This snippet code is credited to Scott’s Hanselman, This Resolve URL function is used where you want to implement it on your business layer.

Methods:

        #region "Image URL helpers"

        public static string ResolveUrl(string originalUrl)
        {
            if (originalUrl == null)
                return null;
            // *** Absolute path - just return
            if (originalUrl.IndexOf("://") != -1)
                return originalUrl;
            // *** Fix up image path for ~ root app dir directory
            if (originalUrl.StartsWith("~"))
            {
                string newUrl = "";
                if (System.Web.HttpContext.Current != null)
                    newUrl = System.Web.HttpContext.Current.Request.ApplicationPath + originalUrl.Substring(1).Replace("//", "/");
                else  // *** Not context: assume current directory is the base directory
                    throw new ArgumentException("Invalid URL: Relative URL not allowed.");
                // *** Just to be sure fix up any double slashes
                return newUrl;
            }
            return originalUrl;
        }

        /// Works like Control.ResolveUrl including support for ~ syntax
        /// but returns an absolute URL.
        /// 
        /// Any Url, either App relative or fully qualified
        /// if true forces the url to use https
        /// 
        public static string ResolveServerUrl(string serverUrl, bool forceHttps)
        {    // *** Is it already an absolute Url?
            if (serverUrl.IndexOf("://") > -1)
                return serverUrl;
            // *** Start by fixing up the Url an Application relative Url
            string newUrl = ResolveUrl(serverUrl);
            Uri originalUri = System.Web.HttpContext.Current.Request.Url;
            newUrl = (forceHttps ? "https" : originalUri.Scheme) + "://" + originalUri.Authority + newUrl;
            return newUrl;
        }

        /// 

        /// This method returns a fully qualified absolute server Url which includes
        /// the protocol, server, port in addition to the server relative Url.
        ///
        /// It work like Page.ResolveUrl, but adds these to the beginning.
        /// This method is useful for generating Urls for AJAX methods
        /// 
        /// Any Url, either App relative or fully qualified
        /// 
        public static string ResolveServerUrl(string serverUrl)
        {
            return ResolveServerUrl(serverUrl, false);
        }

        #endregion

Usage:

 sb.AppendFormat("
", row.WidgetItemClass);
                        sb.AppendFormat("",
                                            ProductsService.GetProductUrl(row.ProductID),
                                            ResolveServerUrl("~/GetWhiteLabelFile.aspx?whiteLabelFileID=" + row.WidgetItemLinkImageID.ToString()));
                        sb.AppendFormat("
");