C#

interface IA<br />
{<br />
  ... methods, properties, etc of A ...<br />
}<br />
<br />
interface IB <br />
{<br />
  ... methods, properties, etc of C ...<br />
}<br />
<br />
class C : object, IA, IB<br />
{<br />
  private A a;<br />
  private B b;<br />
<br />
  public void MethodOfA()<br />
  {<br />
    a.MethodOfA();<br />
  }<br />
 <br />
  // useful when you specifically request a class in terms of A<br />
  // and B has the same implementation.<br />
  void IA.MethodOfA()<br />
  {<br />
    a.MethodOfA();<br />
  }<br />
 <br />
  ....<br />
}

protected override void WndProc( ref Message m )
{
  const int UWM_HERE_I_AM = 0x1234;
 
  switch( m.Msg )
  {
  case UWM_HERE_I_AM:
    m.Result = OnHereIAm( m.WParam, m.LParam );
    return;
  }
  
  base.WndProc( ref m );
}

class MyThread : ....
{
  // other members
 
  public event EventHandler MyEvent;
  
  protected virtual void OnMyEvent(EventArgs e)
  {
    FireMyEvent(e);
  }
 
  private void FireMyEvent(EventArgs e)
  {
    if( MyEvent != null )
    {
      MyEvent(this, e);
    }
  }
 
  private void SomeCode()
  {
    SomeLengthyProcessing();
 
    SomeMoreProcessing();
 
    // MyEvent occurred let everyone know
    OnMyEvent(EventArgs.Empty);
 
    EvenMoreProcessing();
  }
}

.....
MyThread mt = new MyThread();
 
// attach event listner
mt.MyEvent += new EventHandler(myMethodToExecuteWhenMyEventHappens);
.....
 
private void myMethodToExecuteWhenMyEventHappens(object sender, EventArgs e) {
  // Code to execute when MyEvent occurs
}

class MyEventEventArgs : EventArgs
{
  // data members
  private int myValue;
 
  public MyEventEventArgs( /* arguments */ int myValue )
  {
    // set data members
    this.myValue = myValue;
  }
 
  public int MyValue
  {
    get { return myValue; }
  }
}

class MyThread : ....
{
  // other members
  public delegate void MyEventEventHandler(object sender, MyEventEventArgs e);
 
  public event MyEventEventHandler MyEvent;
  
  protected virtual void OnMyEvent(MyEventEventArgs e)
  {
    FireMyEvent(e);
  }
 
  private void FireMyEvent(MyEventEventArgs e)
  {
    if( MyEvent != null )
    {
      MyEvent(this, e);
    }
  }
 
  private void SomeCode()
  {
    SomeLengthyProcessing();
 
    SomeMoreProcessing();
 
    // MyEvent occurred let everyone know
    MyEventEventArgs e = new MyEventEventArgs(42);
 
    OnMyEvent(e);
 
    EvenMoreProcessing();
  }
}

.....
MyThread mt = new MyThread();
 
// attach event listner
mt.MyEvent += new MyEventEventHandler(myMethodToExecuteWhenMyEventHappens);
.....
 
private void myMethodToExecuteWhenMyEventHappens(object sender, MyEventEventArgs e) {
  // Code to execute when MyEvent occurs
  int value = e.MyValue;
   
  // do something with value
}