Assembly.CodeBase: when is it no file-URI?

Question

Assembly.Location gives a plain path to the assembly. Unfortunately this is empty when running in a shadowed environment, such as unit test or ASP.NET. Hovever, the Codebase property is available and provides a URI that can be used instead. In which cases it returns no URI starting with file:///? Or in other words: what are the cases in which this won't work or will return unusable results?

Assembly assembly = GetType().Assembly;    
Uri codeBaseUri = new Uri(assembly.CodeBase);
string path = codeBaseUri.LocalPath;

Answer 1

It's possible to load assemblies directly over HTTP, such as in a ClickOnce deployment:

Assembly assembly = Assembly.LoadFrom("http://server/app.dll");
Uri codeBaseUri = new Uri(assembly.CodeBase);
Debug.Assert(codeBaseUri.Scheme == "http"); 
Debug.Assert(codeBaseUri.LocalPath == "");
Debug.Assert(assembly.Location == "");

Answer 2

Also, # char is threated as a fragment separator. See http://blogs.msdn.com/ncl/archive/2010/02/23/system-uri-f-a-q.aspx (section 9) for short explanation.

Use Assembly.EscapedCodeBase instead of Assembly.CodeBase to fight it.