Debug a dll using C# 7.0 and build from VS 2017 when consumed by a LightSwitch project that can only run on VS2013

Question

I have a legacy LightSwitch app to work on. It only runs on VS2013 (not even VS2015). I have a new project in VS2017 that exposes an Anti Corruption Layer library as a dll that the LightSwitch project consumes.

When debugging the LightSwitch project, I want to set breakpoints in the cs files of the livrary.

Notes:

1°) VS2013 can't load the dll symbols (even when I select them manually from Debug>Windows>Modules). It says "a matching symbol file was not found in this folder".

2°) I cannot just add the library project into the LightSwitch solution as it target net45 as well as netstandard2.0 and uses C# 7.0

3°) I tried to attach VS2017 to the running LightSwitch app but couldn't find the proper process to attach to. I tried iss and iexplorer but none worked.

Answer 1

Start debugger from code of your library:

System.Diagnostics.Debugger.Launch();

Simply launch your app without debugging and once it reaches the code it will offer to open VS debugger.

I used this approach to Debug managed COM libraries and you can debug even library which is called from bat file.