The Power of (C# Keyword) As

I’ve been coding in C# now for 5 years. Other than with my wife, C# is my longest standing relationship. While I don’t celebrate my anniversaries with C# (yet – though I might on our 10th) I did think that I was familiar, maybe even intimate, with the language. Why then had I never heard of the as keyword.

Previously I would cast object like so

try
{
     Checkbox myCheckBox = (Checkbox)strangeObject;
     //do some clever stuff
}
catch(Exception)
{}

- which works fine. My niggle with this that you’re getting towards using exceptions to manage the flow of code and the seven circle of hell is reserved for coders that indulge in this satanic practice. Enter the angelic keyword as

Let’s do the same thing, this time with our new friend.

Checkbox myCheckBox = strangeObject as Checkbox;

if(myCheckBox != null)
{
 //do something clever
}

The as casts the object but instead of spewing out an exception it gracefully nulls it. Therefore it’s same code but with no exception unpleasantness. I like this a lot better – it’s like wholemeal fibre vs. saturated fats. It’s just a lot better for you.