Hi, I know that the question mark can be used to

Question

Hi, I know that the question mark can be used to

check for item not being null,
Same as:

Action action;
Void execute() => action?.Invoke();

How is this different from :

Void execute() => action!.Invoke();

using exclamation mark instead?

0

21.08.2021

12 ответов

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Shafiq Jetha

You’re basically saying “trust me, I know what I’m doing” to the compiler, but realistically, you’re probably actually saying “hold my beer”.

0

21.08.2021

Keith Stanley

Shafiq Jetha
You’re basically saying “trust me, I know what I’m...

😂😂😂i love this explanation

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21.08.2021

Adnan Al_Beda Автор вопроса

Shafiq Jetha
You’re basically saying “trust me, I know what I’m...

Thanks, so this means that using '!' should raise an error if item is null, unlike '?' which don't execute if null, right? Or there won't be any error in both cases?

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21.08.2021

Wizou

Adnan Al_Beda
Thanks, so this means that using '!' should raise...

my understanding is that "!" is the point where - before that the value could be null - after that, the compiler can consider that the expression (value!) is not null (in a #nullable enabled code) - at the time of ! if the value is null, it raise a NullRefException

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21.08.2021

Ronny Gunawan ️

Wizou
my understanding is that "!" is the point where - ...

it's not just that. it's really an NRT-warning forgiving operator: List<string?> a = new(); List<string> b = a.ToList()!;

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21.08.2021

Wizou

Ronny Gunawan ️
it's not just that. it's really an NRT-warning for...

so what happens if 'a' contained null elements, and you access them in b?

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21.08.2021