MultiImageAddinHostControl_4.cs

private IImageRepository _imageRepository;

/// <summary>
/// Sets the image repository.
/// </summary>
/// <param name="repository">The repository.</param>
/// <exception cref="System.ArgumentNullException">repository</exception>
[ApplicationVisible]
public void SetImageRepository(IImageRepository repository)
{
    if (repository == null)
        throw new ArgumentNullException("repository");

    if (_imageRepository != null)
    {
        _imageRepository.RequestItemImages -= OnRequestItemImages;
    }

    _imageRepository = repository;
    _imageRepository.RequestItemImages += OnRequestItemImages;

    _vm.SetImageRepository(repository);
}

/// <summary>
/// Occurs when a request item images is made.
/// </summary>
[ApplicationVisible]
public event EventHandler<ImageRequestEventArgs> RequestImages = delegate { };  

private void OnRequestItemImages(object sender, ImageRequestEventArgs e)
{
    RequestImages(new object(), e);
}