How to define a property in a class of another class type in c#?

Question

I want to define a property in a class of type another class. for example I have a classA with some properties and I want to declare another class that have a property of type classA.

Answer 1

Passing an object to another
https://code.sololearn.com/c6Iga31L2BS5/#cs

Inheriting static property
https://code.sololearn.com/c52xKD9q6gPB/#cs

Just a couple of ideas

Answer 2

class classB {
public classA var;
}

Answer 3

I wrote it like this before but when I want to initialize properties of var, it doesn't work and var is undefined

Answer 4

classA.
classA CA1 = new class