How to set up ReSharper to allow you to navigate to third-party DLL files and view source lines of code?

Question

This confusing feature in ReSharper claims to let you browse external sources from within Visual Studio, see External Sources (ReSharper Web Help).

But, I don't understand what values to set for the folder substitution option. (Resharper - Options - External Sources - Advanced)

When I try navigating to source, I keep getting the message:

PdbNavigator: No sources found in debugging information for in assembly

(This is almost a duplicate of Stack Overflow question Visual Studio - Attach source code to reference, but that post did not explain HOW to attach external sources.

Answer 1

This is tricky, and I finally figured it out:

1. Click "Show current path settings and PDB files binding" and look at where the PDB points to for source.
2. Add a folder substitution where the source code is where the PDB says the source code is (probably a path not on your computer, but on the system that compiled the DLL file and PDB). Set the target to the source you downloaded.

Here's a screenshot: