Get The Current Application Virtual Path in ASP.Net

Question

Inside the Application_Start of my Global.asax.cs, I am trying to get the current application path using:

var virtualPath = HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority)
                          + HttpRuntime.AppDomainAppVirtualPath;

This will return for example: http://localhost:99/MySite/

I will then use this URL and do the following:

var pageToHit = virtualPath + Pages\MyOtherPage.aspx 
var client = new WebClient();
client.DownloadData(dummyPageUrl);

All this is fine when I run the project in IIS 6 or the Visual Studio built-in web server, however things go crazy in IIS 7 as I get a "System.Web.HttpException: Request is not available in this context".

I am aware of this thread: Request is not available in this context

However, I was wondering if anyone had any idea on how to do the above without changing the project to run in classic mode.

Solution

You cannot access the absolute url of the current request inside Application_Start when running in integrated mode. You could access the virtual path name using HostingEnvironment.ApplicationVirtualPath but not an absolute url. Here's an article which explains a common workaround. As explained in the article you have 2 possibilities:

1. Change your application code to not use the request context (recommended)
2. Perform the initialization in Application_BeginRequest using a lock and a singleton to ensure that this initialization is performed only once for the entire lifetime of the AppDomain. Here's a similar thread discussing this second approach.