Dynamic Lang. Runtime vs Reflection

Question

I am planning to use dynamic keyword for my new project. But before stepping in, I would like to know about the pros and cons in using dynamic keyword over Reflection.

Answer 1

In most cases, using the dynamic keyword will not result in meaningfully shorter code. In some cases it will; that depends on the provider and as such it's an important distinction. You should probably never use the dynamic keyword to access plain CLR objects; the benefit there is too small.

The dynamic keyword undermines automatic refactoring tools and makes high-coverage unit tests more important; after all, the compiler isn't checking much of anything when you use it. That's not as much of an issue when you're interoperating with a very stable or inherently dynamically typed API, but it's particularly nasty if you use keyword dynamic to access a library whose API might change in the future (such as any code you yourself write).

Use the keyword sparingly, where it makes sense, and make sure such code has ample unit tests. Don't use it where it's not needed or where type inference (e.g. var) can do the same.

Edit: You mention below that you're doing this for plug-ins. The Managed Extensibility Framework was designed with this in mind - it may be a better option that keyword dynamic and reflection.