How to compile a piece of code without compile the whole code

Microsoft has provided a mechanism you can use for this called "COM". Using this (obsolete) technology, you define a set of interfaces, write an original COM object that implements all of the interfaces, and the client code that uses this object. You can later update your object or write a new one, which your existing code can use without recompilation.

More blah blah blah on COM can be found here[^].

Some programming examples can be found here[^].

... or ask Google.

Usually if you want to support something like that you will add some scripting (macro) language support to your application...

Or your application can support some plugins architechture. But you won't use that direction for a typical application that is intented for general users (and not developpers).

I think that a macro language that your parse from your code might be appropriate in your case if you want to give orders to the controller like move left 50 degrees, move up 10 degrees...

But if the target audiance is general user, then it migth be better to have a front-end UI where the user can pick items from a list and execute them either in connected mode (the hardware device move) or in preview mode (you only update the representation on screen).

1) The Windows operating system supports the mechanism known as Dynamic Link Libraries which allows a library to be kept separate (in a distinct file) from the main application.

Binding with the functions in the library is done at run-time, the main application being able to scan the DLL file and find the entry points (functions if you like) that it contains.

Binding can even be done in a dynamic way, i.e. by invoking the LoadLibrary system function when you want. The FreeLibrary allows you to later release the DLL.

Using this mechanism, you could very well encapsulate part of your code in a DLL that your main application will load and unload when needed, allowing you to edit the DLL code and rebuild it in the meantime.

To achieve this, you need to fully understand the topics of creating and using DLLs. http://msdn.microsoft.com/en-us/library/ms682589(v=VS.85).aspx[^]

2) Another, much easier solution is offered to you: the Microsoft Visual Studio IDE features an amazing debugging mode known as Edit and Continue: it allows you to modifiy the code while running in a debug session and continue with the modified code compiled on the fly. It is not bulletproof but might be what you are looking for.

See http://msdn.microsoft.com/en-us/library/bcew296c(v=VS.80).aspx[^]