Calling functions in C# ternary operator

Question

Why is this code not valid? Pretty sure it's legit in C /C++

Pseudocode:

String s = Console.ReadLine();
int x = 0;
Int32.TryParse(s, out x) ? Console.WriteLine("Foo") :  Console.WriteLine("bar");

Perhaps you mean `Console.WriteLine` instead of `Console.writeline`. — Codor, Jul 19 '16 at 06:27
It's pseudo code. I'm typing this out on mobile. The question is about the ternary operator, the code will compile fine as an if-else — aCuria, Jul 19 '16 at 06:30
@Hank sorry about that, I thought the question was simple enough that it could be answered without having to compile it. I don't recall posting any error messages though — aCuria, Jul 19 '16 at 06:51

Salah Akbari · Accepted Answer · 2016-07-19T06:45:59.840

5

The ternary operator is used to return values and those values must be assigned.

If you want to invoke void methods in a ternary operator, you can use delegates like this:

String s = Console.ReadLine();
int x = 0;
(Int32.TryParse(s, out x) ? new Action(() => Console.WriteLine("Foo")) : () => Console.WriteLine("bar"))();

edited Jul 19 '16 at 06:45

answered Jul 19 '16 at 06:33

Salah Akbari

score 1 · Answer 2 · answered Jul 19 '16 at 06:31

1

console.writeline return void.. The conditional operator (?:) returns one of two values depending on the value of a Boolean expression

answered Jul 19 '16 at 06:31

marius

score 0 · Answer 3 · edited May 23 '17 at 10:28

0

As discussed here, in C#, not every expression can be used as a statement.

edited May 23 '17 at 10:28

Community

answered Jul 19 '16 at 06:30

Codor

3 Answers3