C# Null-Conditional Operator (? Operator) Explained!

[@WhitefoxSpace]

Dude you are an *incredible* teacher.

[@jfversluis]

Thank you so much! 🥰

[@jaimemenendezalvarez5796]

I came here to resolve a question and I left with another. I did not know that it was possible to define an object of the same class within the definition of the class itself. Either way, thanks for resolving my concerns about Null-conditional operators

[@jfversluis]

Haha the more you know... Glad you enjoyed it! Any other questions you might have?

[@johnb2572]

Nice, very useful. Thank you.

[@jfversluis]

Glad it was helpful!

[@itamarcus]

good tips... and now we also know that Gerald loves gardening ^_^

[@jfversluis]

Hahaha actually… he does not 😜

[@klasseka]

I often use combo of operators ?. and ?? . It`s useful if need to react on null like Console.WriteLine(person?.Name ?? "A person has no name");

[@jfversluis]

That makes total sense! I didn't want to take on too much in one video, but more on this is coming :)

[@BijouBakson]

Thank you.

[@jfversluis]

Thanks for watching!

[@dolphinsoft_Youtube]

perfect

[@jfversluis]

Thanks!

[@hrishikeshgarud7177]

Nice website.

[@jfversluis]

Glad you like it!

[@MrBigdogtim69]

Does it make sense to declare properties with the ? operator? For example, public class foo{ public string bar? {get; set; } }. If so - how do you assign to bar?

[@jfversluis]

Great question Tim! And in fact this doesn't really have much to do with the thing I'm showing here. It is somewhat related. By declaring a member like that you make it nullable when it usually isn't. Like in your example, a string gets assigned the default value. In the case of a string the default value is null already though because it’s a reference type. But for value types it will have a default value. By adding the question mark, it now is nullable, so the default value will be null and you can assign null to it. To be honest I don't find myself needing it that often, but it comes in handy sometimes. Have you used it? More info here: docs.microsoft.com/dotnet/csharp/language-reference/builtin-types/nullable-value-types

[@--Eric--]

@Tim Belvin Probably a copy/paste error but the '?' goes on the type, not on the variable name. 'string? bar' The '?' has nothing to do with `how´ you set a variable, it only adds a value (null) you are allowed to use. valid 'int' values: -2147483648,...,-2,-1,0,1,2,...,2147483647 valid 'int?' values: -2147483648,...,-2,-1,0,1,2,...,2147483647 and null 'string' is only allowed to have 0-length strings "", up to n-length "..." 'string?" can besides the above x-length strings also be set to null It's up to you if you want to have this extra null-value to use for some non existent value or error etc. It may be a different thing for you if bar is "" or null (i.e. is "" an error or not). /* The above is not strictly correct, it's possible to get around, but this is the spirit of '?' nullable value types. */

[@jfversluis]

@@--Eric-- Ah you're right :) my answer only makes sense if it goes on the type not the variable name. Overlooked that the first time

[@jfversluis]

You’re right! Updated it a bit