C# How to execute code after object construction (postconstruction)

Question

As you can see in the code below, the DoStuff() method is getting called before the Init() one during the construction of a Child object.

I\'m in a situation where I

Answer 1

Correction: As per this answer, you can't determine when the base class's constructor is invoked during construction of the subclass.

E.g. This doesn't work:

public Child()
// DoStuff is called here after Init
// because of the overridden default constructor
{
    Init();
    base();
} 

So, yes, as others have noted, if sequence of events matters, then the base class needs to be able to accommodate that by declaring abstract methods in order, or (better yet) by having the child class's implementation of DoStuff represent the sequence of events:

protected override void DoStuff()
{
    Init();
    base.DoStuff();
}

Answer 2

As others have mentioned, you should use a Factory Pattern.

public class Parent
{
    public Parent()
    {            
    }

    public virtual void PostConstructor()
    {
    }
}

public class Child : Parent
{
    public override void PostConstructor()
    {
        base.PostConstructor();

        // Your code here
    }
}

public void FactoryMethod<T>() where T : Parent
{
    T newobject = new T();
    newobject.PostConstructor();
}

Answer 3

I would strongly suggest use Factory like a pattern.

If it's possible:

1. Push all your childs and abstract class into separate assembly.

2. Declare ctors of childs like internal methods, so no one out of that assembly is can construct them just by calling ctor.

3. Implement the Factory class to construct for caller specified objects type, which obviuoly will forse calling of abstract DoStuff() method after actual creation of anobject, but before returning it to caller.

Good thing about this is that: It will give you also additional level of abstraction, so if in the future you will need some more functions call or any other type of logical complexity, what you will need, is just add them into your Factory class.

That is.

Regards