C#

public class Singleton : Component
{
   private static SingletonInternal instance = null;
   private static int instancecount = 0;

   private class SingletonInternal : IDisposable
   {
      //just the normal "instance" implementation

      public void SomeMethod()
      {
      }

      public void Dispose()
      {
         // free unmanaged resources
      }
   }

   public Singleton()
   {
      if (instance == null)
         instance = new SingletonInternal();
      instancecount++;
   }

   public void SomeMethod()
   {
      instance.SomeMethod();
   }
   
   protected override void Dispose(bool disposing)
   {
      if (!this.disposed)
      {
         if (disposing)
         {
            // free managed resources
         }
         instancecount--;
         if (instancecount == 0)
            instance.Dispose();

         this.disposed = true;
      }
   }
}