What's a best practice for using dynamic type in ASP.NET MVC 4?

Question

As we know Microsoft introduced the dynamic type a long time ago. And I also applied it in some case in the ASP.NET MVC application. But to me, it is not good for all cases. In specific, it's seen to be violating some basic principals like The Acyclic Dependencies Principle. For example, I have a package A that using package B, then in B I use dynamic and reference to A. It work fine. So the question is how do I use the dynamic type in correct way?

Answer 1

I think the dynamic keyword is good, but we have to using it very careful, like Mike mention as above. I used it on some small examples. When we use it, and we know it, so when somebody call to it, he/she have to know what kind of object that use in dynamic. Hope this help.

Answer 2

Speaking from experience: don't do it. Seriously, sooner or later you will regret. Each time I decide to use dynamics I found it was a mistake. Using dynamics makes refactoring a nightmare, and you lose the biggest advantage which is type safety. Errors will show up in runtime instead of during compilation.

It's usually ten times better to refine your design and use oop principles or try to find some common interfaces.

It should be used only to simplify working with dynamic languages such as java script. Otherwise it is bad for your program performance and your mind sanity :)

So the best practice with dynamics is: try avoiding using them

Answer 3

Dynamic is not a type, it's syntactic sugar. The type will be object, but the compiler will put in a lot of code to detect the actual type of the variable at runtime.

It's meant to be used when you don't know the actual type, for example is used by the dynamic languages running on top of .Net.

It can be abused, as a lazy shortcut (but for that use var ) but you'll get a performance penalty in that case. Long story short, it should be used when you can't solve a problem easily with strong typing.