Hi Jerry,
Thanks for your interest in Syncfusion products.
We have analyzed your scenario and have the dashboard sample using LINQ to SQL datasource. Please refer the dashboard sample from below location and let us know if you have any queries,
Dashboard Sample location:
<InstalledLocation\Syncfusion\EssentialStudio\VersionNumber\Windows\Grid.Grouping.Windows\Samples\Product Showcase\LINQ To SQL Demo>
Regards,
Piruthiviraj