internal override void CopyValue(AbstractDataContainer fromContainer, int fromIndex, int toIndex)
			{
				base.CopyValue(fromContainer, fromIndex, toIndex);
				_values[toIndex] = ((BitDataContainer)fromContainer)._values[fromIndex];
			}
		internal virtual void CopyValue(AbstractDataContainer fromContainer, int fromIndex, int toIndex)
		{
			_nullValues[toIndex] = fromContainer._nullValues[fromIndex];
		}