/// <summary>
 /// Dispose this if a view else operation is illegal
 /// </summary>
 /// <exception cref="FixedSizeCollectionException">If not a view</exception>
 public void Dispose()
 {
     if (underlying == null)
     {
         throw new FixedSizeCollectionException();
     }
     else
     {
         innerlist.Dispose();
     }
 }