C#: How do I use a method, check if return is null, and set value in one line using lambda and C# Null Propagation

Question

Is this possible in one line of code ? null : yourHelpfulAnswer

Thank you in advance.

var x = await Foo_Get() == null ? 123: Foo.SomeProperty;

Just seems like there is a much better way than:

var myVal = 123;
var foo = await Foo_Get();
if(foo != null) myVal = foo.SomeProperty;

I recommend you take a look into: https://stackoverflow.com/questions/446835/what-do-two-question-marks-together-mean-in-c — Isaí Hinojos, May 22 '20 at 18:08
var x = await Foo_Get() == null ? 123: Foo.SomeProperty; is not functioning, just pseudocode of what I am trying to accomplish. — Vert, May 22 '20 at 18:10
Just for fun, I would suggest you check out the "Null-Object" pattern. That might/might not work for you. I know the pattern gets a lot of flack for generating to much overhead. But really, you might disagree. — Morten Bork, May 22 '20 at 18:10
I think everything looks good just make sure that Foo_Get() is async Task<> function — Wowo Ot, May 22 '20 at 18:11

score 4 · Accepted Answer · answered May 22 '20 at 18:10

4

That should do the trick:

var myVal = (await Foo_Get())?.SomeProperty ?? 123;

Simplified:
? = if value on left is null use null, otherwise use property
?? = if value on the left is null use the value on the right instead.

answered May 22 '20 at 18:10

Vincent

Thank you! Tested and works. So quick I can't even mark as the answer for 5 more minutes. – Vert May 22 '20 at 18:15

score 0 · Answer 2 · answered May 22 '20 at 18:15

0

You can use the null coalescing operator to set myVal:

var myVal = (await Foo_Get())?.SomeProperty ?? 123;

answered May 22 '20 at 18:15

NetMage

2 Answers2