Question

This could even be a simple question even a school boy can answer.

What is the similarities and differences between “ForEach” and “Using” (asked in an interview).

My assumption was

1)Both are enumerable

2) Using can handle memory resources,but foreach can’t.using supports IDisposable,foreach can’t.

I wish to know the answers.

Answer 1

Similarities:

• they are both logical code expansions, providing boiler-plate code of otherwise complex scenarios
• both involve a hidden variable introduced by the compiler: for the iterator and the snapshot of the disposable object, respectively

But that is about where it ends…

• using demands IDisposable; foreach might trigger from IEnumerable[<T>], but is actually duck typed (you don’t need IEnumerable for foreach)
• using has a predictable try/finally construct; foreach might involve a Dispose() if the iterator is IEnumerable<T>

If anything, I’d say using is closer to lock than to foreach.