If object is SomeType vs. object as SomeType

Question

Possible Duplicates:
Direct casting vs 'as' operator?
casting vs using the 'as' keyword in the CLR

I know I can do the following:

if(someObject is Bar)
{
    Bar b = (Bar)someObject;
    //Use b
}

and also:

Bar b = someObject as Bar;
if(b != null)
{
    //Use b
}

Is one preferable over the other, if I assume I'm just going to reference the someObject in another variable?

EDIT: By preferable, I'm meaning following conventions, performance, chance for bugs, and readability.

@Jon Skeet @Brain Rasmussen I apologise, they did not appear on the 'related questions' nor on my searching. @digEmAll I'm somewhat new to C#, couldn't I use the second one if I used a nullable Bar? — PrettyPrincessKitty FS, May 18 '11 at 10:50

score 1 · Accepted Answer · answered May 18 '11 at 10:49

1

The first version has two checks, whereas the second one has only one check.
--> The second one is preferable.

answered May 18 '11 at 10:49

Daniel Hilgarth

1 Answers1