Hi Michael,
Apologize for the delay caused.
We regret to let you know that GridControl does not have support to populate in design time(through XAML). But you can find an alternate control “SfDataGrid Control” which achieves your requirement.
Please find the below UG link to know more about the control.
Link: http://docs.syncfusion.com/wpf/sfdatagrid/overview
Please let us know if you need any clarifications.
Thanks
Kanimozhi B