/// <summary>
 /// Dispose disposable properties
 /// </summary>
 /// <remarks>
 /// Ensure the unit of work is disposed
 /// </remarks>
 protected override void DisposeResources()
 {
     _mediaTypeRepository.Dispose();
     _tagRepository.Dispose();
     _contentXmlRepository.Dispose();
     _contentPreviewRepository.Dispose();
 }