Wie verwende ich eventhandler aus Basisklasse

Question

Ist es möglich, ChangeHappend in meiner abgeleiteten Klasse zu verwenden. Wenn das so ist, wie?
Wenn nicht, was soll ich stattdessen tun?

class Base 
{ 
    public delegate void ChangeHandler(object sender); 
    public event ChangeHandler ChangeHappend; 

    private int _foo; 
    public int Foo 
    { 
     set 
     { 
      if (_foo == value) return; 
      _foo = value; 
      ChangeHappend(this); 
     } 
    } 
} 

class Derived : Base 
{ 
    private int _bar; 
    public int Bar 
    { 
     set 
     { 
      if (_bar == value) return; 
      _bar = value; 
      ChangeHappend(this); // This line gives an error. How can I use ChangeHappend here in Derived? 
     } 
    } 
} 

Answer 1

Verwenden Standardmuster: Auf [Eventname]

public class MyBaseClass { 
    protected virtual void OnSomethingHappend(EventArgs e) { 
     EventHandler handler = this.SomethingHappend; 
     if (null != handler) { handler(this, e); } 
    } 
    public event EventhHandler SomethingHappend; 
} 

public MyDerivedClass : MyBaseClass { 
    public void DoSomething() { 
     this.OnSomethingHappend(EventArgs.Empty); 
    } 
}