Step into referenced .Net 3.5 assembly from Asp.Net 4 project

Can I step into .net 3.5 assembly that is referenced by an Asp.Net 4 application?

We have a bunch of dll's that are used in our projects. The assemblies are targeting framework 3.5. I also have the source code for the assemblies. In framework 3.5 projects I could step into the referenced assemblies, even though the project only referenced the assemblies, if I set the Solution->Properties->Debug Source Files -setting to the location of the assemblies' source code files. Now in an Asp.Net 4 project the same doesn't work. I cannot step into the referenced code.

If I open a source file directly in Visual Studio (File-Open->navigate to source code location) and put a breakpoint in a file I know will be run it says "...breakpoint will not be hit. No symbols have been loaded..." when attaching to w3wp.exe and se开发者_StackOverflowlecting to debug "Managed (4.0)". If I attach it to "Managed (2.0)" the breakpoint does not hit either.

Please advice, Mathias

So you have your compiled dlls under 3.5 framework, and also you have source code for them, right? Have you tried opening a solution, which contains the project, and attaching it to w3wp.exe? Also ensure your dlls were compiled with debug information.

Another way is to use .NET Reflector to step in dlls without source code at all.