Accessing class variable from another class

Question

I have a class A that contains a List field.

public class A { public List<int> list = new List<int>(); }

I would like to remove an element from the list from class B without making the list in class A static. How can I do that?

Why do you need to make it static? you set it to public so anyone with an instance of class A can already get to list and modify it. — Gilad Green
– Gilad Green, Commented Jun 27, 2016 at 11:39

Salah Akbari · Accepted Answer · 2016-06-27 13:14:03Z

You could create an instance of class A inside a method in class B. Then you could access the list field, like this:

public class B { void method() { A a = new A(); int item = 2; a.list.Remove(item); } }

Nazar Merza · Accepted Answer · 2016-06-27 15:00:20Z

A more OOP solution for this problem would be:

public class A { private List<int> list = new List<int>(); List<int> getList(); void setList(List<int> list); }

Then in the code where it is used,

A a = new A(); List<int> list = a.getList(); modify list as you want a.setList(list);

Robert Moskal · Accepted Answer · 2016-06-27 20:48:17Z

If you don't mind instantiating it, it's simply

A a = new A(); a.list...

If you don't want to instantiate a new one, you can pass an existing instance to B on its constructor:

public class B{ private A myA; public B( A a) { this.myA = a; } public doSomething(){ this.myA.... } }

Now you can use A as a field of B.

3 Answers 3