Reference a big DLL for a single method

Question

I want to use a single method from a big Class library-dll in C#.

Are there any drawbacks of performance or anything else?
Should I "read" the method code with reflection tool and copy-paste it to my project?

Update: The hard disk space isn't an issue. My application is web app.

Answer 1

The costs are disk space, load time and memory footprint. The JIT compiler will only compile what you call (there may by caveats to this, but it certainly will not compile the entire assembly). It's your call as to if it is worth your while to 'rip' out the method you need. Remember of course this could be a rabbit hole, by that I mean this method is likely to use other classes in its assembly so it may not be as simple as you think to extract the code you need.

Answer 2

Bah, extreme hacking needs in extreme cases. Copy methods code (if this is possible) is extreme hacking, imo.

1. If just frustration to use unnecessary memory, but basically pretty affordable solution, do it like you continue doing. Simple and easy.

2. If there are memory issues, and the method is not called too frequently (what is too frequently depends on your project) you can try to load it in external AppDomain, and unload that domain one time you finished with it. Sure you need take care of IPC management, in this case. Nothing comes free in this world.

3. You can try do what you wrote. User Reflector (or similar software), get the methods C# code and create its clone. All this supposing that method doesn't use DLL's internal's structures, states or whatever, cause in that case the story becomes fairly complicated.

Good luck.

Answer 3

Are there any drawbacks of performance or anything else?

The only one that is actually important is the size of your distributable, if it matters to you. (Users downloading a 30 MB file instead of a 2 MB one). Performance differences will be negligible. Assembly binding and verifying the Strong Name (if it's signed) hash may take longer, but unlikely to be noticeable to a user.

Should I "read" the method code with reflection tool and copy-paste it to my project?

Probably not; most licensing terms prohibit reverse engineering and/or only partial distribution. Check the license, if any, to see if you can even do it first.

Answer 4

No, leave that up to the JIT compiler. It is already selective about what IL actually gets turned into machine code, it only compiles what actually executes. You'll lose a bit of virtual memory address space but that doesn't cost anything, it's virtual. You don't pay for what you don't use.