How to get key value in a master datagrid from a detail datagrid?

[John Dalberg]

I have a nested datagrid in a datagrid. Each row in the master datagrid
will have a child datagrid. One of the columns in the child datagrid has a
copy of the key of the master row.


However when the child datagrid is empty and a user needs to a add a new
row, I have no reference to which master row they are in.

How do I reference the Datakeys collection of the master datagrid and the
needed index when a user clicks a button in the child datagrid? My add
button is in the footer of the child datagrid.

John Dalberg