Comments on: CSharp VAR Misconceptions

By: Mitch

Mitch — Wed, 09 Sep 2009 15:59:57 +0000

@Dennis

var index = 1;

should be avoided only WHEN index is a constant.

By: Dennis

Dennis — Wed, 09 Sep 2009 15:52:34 +0000

I use “var” a lot, except some foreach iterators to “xxxCollection” which “var” cannot works very well.

In case I cannot use “var”, or it does not look very well; I should consider to break the method into smaller pieces and renaming stuffs.

“var” really save a lot heartbeat from long type name (e.g. generic)
“var” save some time when we extract a new interface from an object. (especially with a factory method)

“var index = 1;”
should be prevented, because “1″ should be a constant.
const int FOO=1; // I mean it
var bar= FOO;

By: gunteman

gunteman — Wed, 09 Sep 2009 08:58:40 +0000

@Mitch

Yes, just making sure…

CodeRush Express (free) features a “Make Explicit” function which can resolve “vars” when you feel like having the type explicitly declared.

By: Eric Smith

Eric Smith — Wed, 09 Sep 2009 08:47:27 +0000

The initial requirement for var was to make things like Linq possible. These days it’s just a nice way of applying the DRY principle – why repeat yourself when you don’t have to? On the other hand though, if it is not pretty clear what type we’re dealing with (other than when using anonymous types of course), then it probably makes sense to be explicit about the type.

By: Mitch

Mitch — Tue, 08 Sep 2009 21:19:12 +0000

@gunteman

I think we all know what he meant.

By: gunteman

gunteman — Tue, 08 Sep 2009 21:12:26 +0000

No, it doesn’t save you from casting, it saves you from explicitly declaring.

By: Jaspio

Jaspio — Mon, 07 Sep 2009 13:10:54 +0000

I don’t use var that much either. Except in foreach iterators:

foreach (var item in collection) {}

It saves a lot of trouble casting to the right type there.
Good point on the right-side assignment though!