Question

I have a BasePage class which all other pages derive from:

public class BasePage 

This BasePage has a constructor which contains code which must always run:

public BasePage() {     // Important code here } 

I want to force derived classes to call the base constructor, like so:

public MyPage     : base() {     // Page specific code here } 

How can I enforce this (preferably at compile time)?

Answer 1

The base constructor will always be called at some point. If you call this(...) instead of base(...) then that calls into another constructor in the same class – which again will have to either call yet another sibling constructor or a parent constructor. Sooner or later you will always get to a constructor which either calls base(...) explicitly or implicitly calls a parameterless constructor of the base class.

See this article for more about constructor chaining, including the execution points of the various bits (such as variable initializers).