我可以从实例化的类继承吗？

Question

I'm trying to inherit from an instantiated class. Why is the value of Inherited , in the code below, a null value? Is there a way to do this correctly?

namespace Sample {
    public class Class1 {
        static void Main() {
            Class2 SecondClass = new Class2();
            SecondClass.StartSomething("hello world");
        }
    }

    public class Class2 {
        public string Inherited;
        public void StartSomething(string value) {
            Inherited = value;
            InheritSomething();
        }
        public void InheritSomething() {
            Class3 ThirdClass = new Class3();
            ThirdClass.DoSomething();
        }
    }

    public class Class3 : Class2 {
        public void DoSomething() {
            Console.WriteLine(Inherited);//when complied Inherited is null
            Console.ReadLine();
        }
    }
}

Answer 1

Inheriting occurs at compile time. (Therefore 'Inherited' does not have a value yet) Values are assigned at run-time.

Answer 2

Inheriting from a class does not inherit the INSTANCE of that class at instantiation of the inherited class. Instead, you'd need to pass along the instance of that class. One option is to inject it into the constructor of class 3

public class Class1
{
    static void Main()
    {
        Class2 SecondClass = new Class2();
        SecondClass.StartSomething("hello world");
    }
}

public class Class2
{
    public string Inherited;
    public void StartSomething(string value)
    {
        Inherited = value;
        InheritSomething();
    }
    public void InheritSomething()
    {
        Class3 thirdClass = new Class3(this);
        thirdClass.DoSomething();
    }
}

public class Class3 : Class2
{
    private Class2 _class2;

    public Class3(Class2 class2)
    {
        _class2 = class2;
    }

    public void DoSomething()
    {
        Console.WriteLine(_class2.Inherited);
        Console.ReadLine();
    }
}