c# what is the difference between "!" operator and "?" operator?

Question

What is the difference between these operators?

var c = foo?.Prop1;

var c = foo!.Prop1;

Btw, Prop1 is an int.

`!` tells the compiler: "trust me, this isn't null" but at runtime an exception can happen if you've lied. `?` handles a possible null value, so that everything after it is also null. — Tim Schmelter, Oct 24 '22 at 14:01

Dmitry Bychenko · Accepted Answer · 2022-10-24T14:05:13.190

4

Well ? is null conditional when ! is null forgiving operators:

So if foo is null

var c = foo?.Prop1; // c will be null (c will be of type int?)
var d = foo!.Prop1; // exception will be thrown (d is int)

edited Oct 24 '22 at 14:05

answered Oct 24 '22 at 14:01

Dmitry Bychenko

1

Also worth mentioning that if Prop1 is an int, than c is a nullable int and d is an int . – Zohar Peled Oct 24 '22 at 14:04

1 Answers1