Visual Studio - Attach source code to reference

My C# project references a third-party DLL for which I have the source code. Can I somehow tell Visual Studio the location of that source code, so that, for example, when I press F12 to open the definition of a method in the DLL, it will open up the source code, instead of opening up the "Class [from metadata]" stub code?

How do I create a .PDB file in Visual Studio?

In a developer command prompt, you can use the mspdbcmf.exe tool to generate a full PDB from this limited PDB. In Visual Studio, use the Project or Build menu items for generating a full PDB file to create a full PDB for the project or solution.

If you use ReSharper, you can enable it by going to ReSharper / Options / External Sources, and move up "Sources from symbol files". Then in the tab "Sources from symbol files", click "Advanced" and there you can map source folders.