Comments on: Caveats of C# 4.0 optional parameters

By: .Net Training in Chennai

.Net Training in Chennai — Wed, 19 Dec 2012 13:37:00 +0000

C# does not
support comma-separated gaps in the argument list.

By: My Daily Shared Bookmarksfboiton's blog | fboiton's blog

My Daily Shared Bookmarksfboiton's blog | fboiton's blog — Sat, 07 Jul 2012 20:11:51 +0000

[...] Caveats of C# 4.0 optional parameters | Jimmy Bogard’s Blog – [...]

By: Anonymous

Anonymous — Tue, 19 Jul 2011 12:00:00 +0000

Nullable types are there for ya! You can do int? instead of int foo = 0

By: Jerome Meyers

Jerome Meyers — Mon, 18 Jul 2011 06:33:00 +0000

You write: “However, I still have to deal with the user not applying the filter, so I have some code to deal with this.” So… how do you get around this? This is exactly the problem I am encountering. I can’t use optional parameters… so, what do I do?

Thanks,
jeromeyers

By: Sam

Sam — Fri, 20 Aug 2010 21:21:10 +0000

Argh, I just got burned by CS0854. Boo urns!

By: Graham

Graham — Fri, 21 May 2010 09:48:34 +0000

I’ve seen some really insidious bugs caused by, admittedly bad, use of optional parameters (in VB6). Where the method signature had changed but the calling code hadn’t, meaning the arguments had shifted one to the left (or right). Like anything, you just have to be careful how you use it.

By: bogardj

bogardj — Thu, 20 May 2010 19:09:00 +0000

@Brendan

In the original code, the input was a variable, but the pattern was a literal. Well-named variables still won’t guarantee I don’t accidentally switch the order when I call the method, however.

By: Brendan Enrick

Brendan Enrick — Thu, 20 May 2010 18:29:31 +0000

With the RegEx example there is something else that’s been built into every version of C# which also allows us to know which one is the pattern and which one the input.

I think the technical name is “variables”. Once we extract those literals into variables like you obviously do in your production code it becomes very obvious which parameter is which. (I admit we can’t at a glance tell if you mixed them up though. I hope you tested the code and made sure it worked though.)

By: joe

joe — Wed, 19 May 2010 19:10:12 +0000

VB has had optional parameters since before it was a .net language. And they were frequently used as a hack to work around the lack of method overloads.

By: For #2 I'd say OPs shouldn't be used

For #2 I'd say OPs shouldn't be used — Wed, 19 May 2010 13:55:51 +0000

If it causes a recompile when its not even a relink, that the set of signatures for each class/method are identical, then it’s not worth it.