WPF RowDetailTemplate Question

I have 2 list:

List list1 contains Pare开发者_Python百科nt object with Property ID

List list2 contains Child object with Property ParentID

list1 is used as ItemsSource in a DataGrid and I need to be able to show all items in list2 in a RowTemplateDetail where items in list2 ParentID = list1 ID.

I have read a lot of examples but commonly the the Model has a property Children that contains list2 but I cannot do it in my project (requirement specific). We are using MVVM btw.

Any input would be appreciated

Thanks!