代码隐藏比内联代码更快吗？

Question

According to the question: Is C# code faster than Visual Basic.NET code ? Was said that C# and VB.NET generates the same CLR code at the end.

But in the case when I'm using codebehind and inline code, are there different performance (ignoring the language used)?

Answer 1

Inline code can require compilation the first time the request is made. After that (or if it's precompiled), there's absolutely zero difference between them.

By the way, even if it requires compilation, the speed difference should be insignificant as ASP.NET will have to compile a source file anyway. The difference will come down to a adding a few lines of code in a large source file!

Answer 2

Yes, ish... If you're compiling at run-time you're always going to be more expensive than something which doesn't have to, but that compile will be cached (if you will) after the first request so you'll get zero difference from then on.

There's probably somone who knows another reason, but to my mind the only realistic purpose for inline is the ability to make hot fixes without a rebuild + redeploy: the kind of thing you might do in small or early stage dev projects. Personally I also find inline just a little... aesthetically displeasing.

Answer 3

The aspx pages have to be parsed and compiled anyway as ASP.Net turns them into classes that inherit from the codebehind (hence the inherit attribute in the page directive) so compilation is necessary in either case. The difference between the two for first runs is going to be negligible unless we're talking about several thousand lines of code.

But I agree with anna: inline is icky.

Answer 4

I'm not sure whether the resulting assembly produced has the AllowOptimize attribute set to on or off. I can find no documentation which indicates this either way.

As such it is possible that the resulting code is not optimized by the JIT in quite the same way.

I doubt this makes a significant difference if any (like I said this might be controlled in some other way) but certainly it could impact certain operations if it, for example, disabled inlining and you had a large, extremely tight loop. Such a construct would probably be a poor choice within an asp.net page so this shouldn't be an issue.

Answer 5

No. Unless you are using web project the site needs to be compiled on the first hit. That affects inline as well as code behind to some extend. After that they run pretty much at the same speed.