title: internal constructor
body: <p>Yesterday I thought it would be nice to implement my own Trigger in a WPF app. I created a class MyTrigger which inherited TriggerBase. TriggerBase is a public abstract class. So inheritance isn't a problem. But the constructors inside this class are marked internal. The compiler throws an error because the is no valid constructor. Why does anyone create a public class but marks the constructors as internal?</p>