[Feature Request] var pattern in IF statement while making null check

[webwarrior06]

Wouldn't it be better if we can create a variable inside IF statement if checked value is not null, like we have in type checking with "is";

To make it clear;

if(Long.Named.Method.Chain.Or.Static.Etc.Value != null var x){

   //...things related to x variable

}

Otherwise, It has to be a variable defined before the IF statement in order not to write long-character variable over and over again. Like this;

var x = Long.Named.Method.Chain.Or.Static.Etc.Value;
if(x != null){

}

[ufcpp]

https://sharplab.io/#v2:EYLgZgpghgLgrgJwgZwLRIMaOQSwG4SoAOsMECAdsgD4ACADAAS0CMA3ALABQ3tAzMwBMjAMLcA3t0bTmLAGyjGAGQD2FAOaMAvAD5GFOABtDnLjMUA5KAFsIAE216Dx0+ZGMAshBgALFQ919IxMpGXcRHygcCkcgl1DpdwBRGAxY5xCzMMYANShDOAh04NcZBOYBWgAWTwAKAEpyySzzaRwwRlrVDQA6K1s7Hq9ffx6IqIoelIwevIKinGRGcQBfRgAPRpbW5ta92QBOWs3SvZXy864VoA=

dup of #1944

[DavidArno]

With C# 8, you can do this with the {} pattern:

if(Long.Named.Method.Chain.Or.Static.Etc.Value is {} x) …

EDIT

Ah, I see @ufcpp already posted a code example showing this in action 😃

[webwarrior06]

Thanks for the info guys. I could not realized something similar was proposed before. 😊
It will be very useful. 👍

[pinkfloydx33]

Can't you already do the following with C#7 (sure, a bit more verbose)?
if(Long.Named.Method.Chain.Or.Static.Etc.Value is var x && x != null) ...

If you know the type, then it's practically the same (but sure, not var)
if(Long.Named.Method.Chain.Or.Static.Etc.Value is SomeType x) ...

[webwarrior06]

@pinkfloydx33 Yeah, the first one is sort of verbose. In fact, the second is better and easy to use for now. We will have this problem solved totally with C# 8 as in @DavidArno's post.

[Joe4evr]

Please close, then.