asked on

?? operator in C#

Dear Experts,

I want to know if I can do this in C#

MyClass
{
public bool ShowHeader {return true;}
}

AnotherClass
{
MyClass myClass = GetInstanceOfMyClass()

return myClass.ShowHeader ?? false;
}

Basically if the myClass object is null i want to return false otherwise the value of myClass.SHowHeader

ASKER CERTIFIED SOLUTION

oxyoo

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tetorvik

Haven't seen such an operator, but for sure you can do something like:

return myClass == null ? false : myClass.ShowHeader;

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Dirk Haest

?? Operator (C# Reference)
http://msdn.microsoft.com/nl-be/library/ms173224(en-us).aspx

SOLUTION

evilrix

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SOLUTION

alb66

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evilrix

^^^ if you function returns a bool type (which I've just noticed it does after re-reading the question :) ), then any of the above answers should suffice... but as I said, if the creation of a class fails then you should consider throwing an exception if this is an error condition and not an expected state.

vbhargav80

ASKER

Hi oxyoo,

The only doubt I have is this. If myClass is null, wouldn't myClass.ShowHeader throw an NullReferenceexception?

oxyoo

@vbhargav80
Well the code states if myClass is not (!=) null then it will call ShowHeader. If it is null then it will return false and ShowHeader will not be called at all. So there shouldn't be any problem.
@alb66
The if-statement is more readable I guess, but I favor (as far as possible) to use only one exit point in a method to reduce complexity and make it less error prone. Not a big deal in a small method like this perhaps. Perhaps a matter of "design-taste" :)