C# – Path of DLL installed to the GAC


How can I get the (physical) installed path of a DLL that is (may be) registered in GAC? This DLL is a control that may be hosted in things other than a .Net app (including IDEs other than VS…).

When I use System.Reflection.Assembly.GetExecutingAssembly().Location, it gives path of GAC folder in winnt\system32 – or in Design mode in VS gives the path to the VS IDE.

I need to get the path where physical dll is actually installed – or the bin/debug or (release) folder for VS.

Reason is that there is an XML file I need to get at in this folder, with config setting that are used both in design mode and at runtime.

Or how is it best to handle this scenario? I have a dubious network location I am using for design mode at the moment… (Don't think that ApplicationData folder is going to cut it (but have the .Net version soved as that's installed via ClickOnce ans can use the Clickonce Data folder) )

Best Solution

If something gets put in the GAC, it actually gets copied into a spot under %WINDIR%\assembly, like


I assume you're seeing something like that when you check the Location of the assembly in question when it's installed in the GAC. That's actually correct. (In .NET 1.1 there was a "Codebase" listed when you looked at a GAC assembly's properties, but that was only to show you where the original file was located when you ran gacutil - it didn't actually indicate what would be loaded.) You can read more about that here.

Long story short, you may not be able to do what you want to do. Instead of looking in relation to some assembly that's being loaded (Assembly.GetExecutingAssembly()), you might want to switch the behavior to look relative to the primary application assembly (Assembly.GetEntryAssembly()) or put the file in some well-known location, possibly based on an environment variable that gets set.