ValuesChanged event

I've been banging my head against a brick wall on this one.

I need to create a composite control that has a ValuesChanged event, which returns a custom EventArgs object that has a property of type List<string, string>.

  public class OptionValuesEventArgs : EventArgs
{
private IDictionary<string, string> m_ValuesChanged = new Dictionary<string, string>();
public IDictionary<string, string> ValuesChanged
{
get { return m_ValuesChanged; }
}
}  
This list is populated via a ValueChanged event on any of my child controls

 &n ...