More readable way to check if class IS NOT of a type?

Question

To check if an object is of a given type in C#:

if(myObj is MyClass)
{
     //....
}

To check if it is not of a given type:

if(!(myObj is MyClass))
{
     //....
}

Is there a more readable way to express the same logic?

For example, if I could write this it would be easier to read.

if(myObj is not MyClass)
{
     //....
}

Might want to check this out if you're okay with casting and then checking for null: http://stackoverflow.com/questions/2550625/cast-then-check-or-check-then-cast — Rethunk, Sep 19 '13 at 22:07
You would like VB.NET better. That's fine, a very capable .NET language. It has a much more sensible precedence for the Not operator, no parentheses required. — Hans Passant, Sep 19 '13 at 22:08
@YuriyGalanter you should post that as an answer. best approach I've seen so far (been googling this). — Reactgular, Sep 19 '13 at 22:09

score 6 · Answer 1 · answered Sep 19 '13 at 22:15

6

You can try using some extention method like this, just to make it more readable as you want:

public static class ObjectExtension
{
    public static bool IsNot<T>(this object o)
    {
        return !(o is T);
    }
}
//Use it
if(myObj.IsNot<MyClass>()){
  //...
}

answered Sep 19 '13 at 22:15

King King

61,710
16
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I've never seen this done before, thanks. Reminds me of traits in PHP. – Reactgular Sep 19 '13 at 22:18
@MathewFoscarini that's some combination of `extension method` and `generics`, I think it's just the most beautiful work-around. – King King Sep 19 '13 at 22:19
You might wish to add a generic constraint to ensure that this is not used with value types. Edit: I guess `is` works with value types after all. But will this cause boxing? – Chris Dunaway Sep 19 '13 at 22:22
@ChrisDunaway wow, after your comment, I've done some test, it's still useful for testing on `struct`, some object has `struct` boxed inside it, we still need to check that case. I don't think there is any problem here. – King King Sep 19 '13 at 22:33

score 4 · Accepted Answer · answered Sep 19 '13 at 22:15

4

You could take the same approach and make it more verbose:

If (myObj is MyClass == false) ;

answered Sep 19 '13 at 22:15

Yuriy Galanter

38,833
15
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I went with this approach. :) – Reactgular Sep 20 '13 at 01:02

More readable way to check if class IS NOT of a type?

2 Answers2