I think I think IContentRepository.GetReferencesToContent can help (not sure about block, though, but it should)
I have used this sql query now to get the required informations, missing untranslated content and their language:
DECLARE @nameOfBlock VARCHAR(MAX) = 'LinkBlock' DECLARE @nameOfBlockProperty VARCHAR(MAX) = 'Reference' SELECT LanguageID, c.pkID FROM tblLanguageBranch lb INNER JOIN tblContentLanguage cl ON lb.pkID = cl.fkLanguageBranchID INNER JOIN tblContent c ON cl.fkContentID = c.pkID INNER JOIN tblContentType ct ON c.fkContentTypeID = ct.pkID WHERE ct.Name = @nameOfBlock AND NOT EXISTS( SELECT 1 FROM tblContentProperty cp INNER JOIN tblPropertyDefinition pd ON cp.fkPropertyDefinitionID = pd.pkID WHERE pd.Name = @nameOfBlockProperty AND pd.fkContentTypeID = ct.pkID AND cp.fkLanguageBranchID = lb.pkID AND cp.fkContentID = c.pkID ) ORDER BY pkID, LanguageID
Would be great if the CMS would support it anyway, so that the customer, who is responsible for the content, can do it himself.
So, you would want editors to be able to select:
And then list all instances of the content type where the property is null or empty.
You could easily create an admin tool for that. However, I have also been in need of the same thing, and have created a tool that (among other things) does this.
I needed to support the customer in a way that he finds untranslated content. So i have asked if it's possible in this thread.
There is no way to list it without using code or the database. So in this case i needed this query to determine all content-ID's which i can use for a link to the CMS.
You can append it to the URL to get a link to the CMS content, for example(649 is the pkID)
But it would be a great help for the customer if he could get a list of all pages/content of a specific block on himself. A good place would be: Admin/Content-Types/Blockname
You could provide a button "Show content that use the block", if you click it it opens a popup which lists all content as hyperlink.
Even better would be to be able to filter for translated/untranslated content of this block.