I try with LabelLocation, but the only solution to display the header with empty collection is to comment the line code of the summary position.
If I comment the command the header appears and the summary is attached to the header.
If I uncomment the command the header disappers and the summary is attached bottom fixed to the datagrid.

Important I use Unbound field without automatic field generation.

Ok, but is not normal that if I comment the line code of summary and the header don't disappers if the collection is empty. No?

Now I try with LabelLocation....

The SummaryDisplayArea has not relation to the Headers. You need to set the LabelLocation property.

If I comment the code:

//datagrid.FieldSettings.SummaryDisplayArea = SummaryDisplayAreas.BottomFixed;

The header don't disappears.

It's normal?

Hello,

Actually I have mislead you. It is working correctly. What the XamDataGrid does is getting the public properties of the class. It does not matter if you have or not a constructors in order for the fields to be generated. Does your abstract class has public properties?