The reason it uses a repeater is because it is a templateable control. The Asp.NET Framework does not have a built-in control that is templateable and only shows one item.

When the CMS repeater loads The ascx transformation, it loads it up like a virtual file and casts it as a class that implements the Itemplate interface. This is a very good way to accomplish what they are doing.

In order to do exactly what you are wanting to do, you will likely need to create a custom web part and add a field to select 1 document then make it so that field will change the value of the where clause used in the CMS repeater.

Writing your own custom web part that uses the same settings as the document repeater web part, but doesn't use the cms repeater (for when you basically want the settings so you can choose what data to get and do anything you want with the result). You will need to study how it is done in the repeater web part and possibly use Reflector to see what methods and things you will need. I have done it before and it was just tedious.


Now, about the "Selected Item" of the repeater. If you are putting these widgets on any document that is not the document you want to be displayed in the widget, then it won't work the way you want. The "Selected Item" is always the document who's document alias matches the current url.

Instead of using the Selected Item transformation, concentrate on making your query return only the one document and use the Item and Alternating Item transformations.

I hope all of this makes sense because it is difficult for me to explain.