Ran across this line of code:
FormsAuth = formsAuth ?? new FormsAuthenticationWrapper();
What do the two question marks mean, is it some kind of ternary operator?
It's hard to look up in Google.
c++null-coalescing-operator
Ran across this line of code:
FormsAuth = formsAuth ?? new FormsAuthenticationWrapper();
What do the two question marks mean, is it some kind of ternary operator?
It's hard to look up in Google.
Best Answer
It's the null coalescing operator, and quite like the ternary (immediate-if) operator. See also ?? Operator - MSDN.
expands to:
which further expands to:
In English, it means "If whatever is to the left is not null, use that, otherwise use what's to the right."
Note that you can use any number of these in sequence. The following statement will assign the first non-null
Answer#
toAnswer
(if all Answers are null then theAnswer
is null):Also it's worth mentioning while the expansion above is conceptually equivalent, the result of each expression is only evaluated once. This is important if for example an expression is a method call with side effects. (Credit to @Joey for pointing this out.)