Visual Studio
- Decompile the dll with ILSpy, find the function you need.
- Attach to Process: w3wp.exe - your application's pool
- Debug -> Windows -> Breakpoints.. -> New -> Function Breakpoint: Type the function name with the namespace you found.
- See the variable in Local window.
DotPeek Plug-in for VS
Tools -> Options -> Debugging -> Uncheck Enable just my code
Tools -> Options -> Debugging -> check Suppress JIT optimization on module load (Managed only)
DNSpy
- A standalone Debugging IDE.
References
- https://michaelscodingspot.com/dotnet-debugging-tools/
- https://michaelscodingspot.com/debug-3rd-party-code-dotnet/