Hi,

You could try to use FindPagesWithCriteria:

            var criterias = new PropertyCriteriaCollection();

            var criteria = new PropertyCriteria();
            criteria.Condition = CompareCondition.Equal;
            criteria.Name = "PageTypeID";
            criteria.Type = PropertyDataType.PageType;
            criteria.Value = _cotentTypeRepository.Load<RoomTypeList>().ID.ToString();
            criteria.Required = true;

            criterias.Add(criteria);


            ServiceLocator.Current.GetInstance<IPageCriteriaQueryService>()
                .FindAllPagesWithCriteria(ContentReference.RootPage, criterias , null, LanguageSelector.AutoDetect());

I don't think FindPagesWithCriteria works with Blocks yet.

It's still a bit messy but this is what I've done:

public IEnumerable<T> GetBlocksOfType<T>()
    where T : BlockData
{
    BlockType blockTypeForT = ServiceLocator.Current.GetInstance<BlockTypeRepository>().Load<T>();
    IList<ContentUsage> contentUsages =
        ServiceLocator.Current.GetInstance<IContentModelUsage>().ListContentOfContentType(blockTypeForT);

    var contentLoader = ServiceLocator.Current.GetInstance<IContentLoader>();
    var contentLoader = ServiceLocator.Current.GetInstance<IContentLoader>();
    List<IContent> blocks = contentUsages
        .Select(contentUsage => contentUsage.ContentLink.ToReferenceWithoutVersion())
        .Distinct()
        .Select(contentReference => contentLoader.Get<IContent>(contentReference)).ToList();

    new FilterPublished().Filter(blocks);
    new FilterAccess().Filter(blocks);

    return blocks.OfType<T>();
    new FilterPublished().Filter(iContents);
    new FilterAccess().Filter(iContents);
            
    return iContents.OfType<T>();
}

And simply call with

IEnumerable<TeaserBlock> content = GetBlocksOfType<TeaserBlock>();

As you notice ListContentOfContentType gives you all versions of the blocks. Hence I make a Select on ToReferenceWithoutVersion and a Distinct.

Instead of your Where on Deleted and Publish I send the content through the built in Filters in EPiServer. In my case my Blocks might not have Templates, hence I use Publish and Access but In if you have Templates/Views for your blocks as well you could simply do FilterForVisitor since it's a composite of the filters Publish, Access and Template. 

Due to the proxy management of Blocks in EPiServer you need to cast back and forth between IContent and T. I prefer using OfType instead of Cast. But that might be me being paranoid.

EPiServer give a disclaimer in the xml comment at class level, but this seems to work:

var db = ServiceLocator.Current.GetInstance<EPiServer.DataAccess.Internal.ContentListDB>();
return db.ListContentOfContentType(contentType, onlyPublished);

I would NOT recommend that. Try to avoid parts of the Episerver API that is within an "internal" namespace.

EPiServer.DataAccess.Internal.ContentListDB

if a block is on a page that is unpublished, i cannot get reference to that page. Any idea ?