To load DLL on a run time or not

Question

Hello,

I need advice about direction in expanding existing program.

I want to enable to users to develop  their own external modules or methods for program,

that would be called and executed from main (existing) program, by selecting modules from

some sort of drop down menu. For this by my knowledge there are two options :

 

1. Enable user to write its own DLL. Load it to program during run time and execute it.

2. Enable to user to write its own program  that receves execute call from main program.

 

In both cases main program passes some parameters to external methods, and accepts result.

 

What would be the better solution, considereing speed and safety.

 

All the best,

Željko Peric