How to access this in constructor?

Asked Aug 06 '22 at 18:08

Active Aug 06 '22 at 18:08

Viewed 15 times

I want to pass the instance of a class this when constructing my class.

class A implements B {

   final C _c = ConcreteClass(b: this);
}

It looks like this cannot be done because this doesn't exist yet. I usually do this in other languages like Java and Kotlin. Any idea how to do this in Dart?

I tried to do it in the constructor but it is the same.

asked Aug 06 '22 at 18:08

J_Strauton

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In short: Declare `late final C _c;` and then initialize it in the constructor's *body*, when `this` is valid: `A() { _c = ConcreteClass(b: this); }` – jamesdlin Aug 06 '22 at 18:12
Wow you can late final? That is amazing. – J_Strauton Aug 06 '22 at 18:13
The duplicate answer question does not even mention assigning `this` within a constructor. I don't think it is a duplicate. – J_Strauton Aug 06 '22 at 18:13
Look again. It explicitly explains that `this` is available in constructor bodies. – jamesdlin Aug 06 '22 at 18:14
Thanks @jamesdlin. You blew my mind with combining `late` and `final`. Super cool. – J_Strauton Aug 06 '22 at 18:16
1

I forgot, you also can do just: `late final C _c = ConcreteClass(b: this);`. Using `late` will make `_c` initialized lazily, after `this` becomes valid. – jamesdlin Aug 06 '22 at 18:17
@jamesdlin you just made my day! This makes me so happy. Thank you! – J_Strauton Aug 06 '22 at 18:19

How to access this in constructor?

0 Answers0