<dataPresenter:XamDataGrid SelectedDataItems="{Binding SelectedItems, Mode=TwoWay}" ...
and then in a ViewModel I tried to clear the selections by
SelectedItems = null;
but its not working
Hello Anthony Cheung,
A similar topic is discussed here where you can find a sample as well:
https://es.infragistics.com/community/forums/f/ultimate-ui-for-wpf/110514/selecteddataitems-binding-does-not-work
Let me know if you have any questions.