Thank you for contacting Syncfusion support.
We have analyzed your query and we regret to inform you that we don’t have Extension support to achieve localization in SfDataGrid LighSwitch. But, we can achieve this by customizing Silverlight sample in lightswitch. We have attached the sample and document link to create customized Silverlight sample in LightSwitch.
Sample link: http://www.syncfusion.com/downloads/support/directtrac/136936/Sample-624836732.zip
Documentation link: http://www.syncfusion.com/downloads/support/directtrac/136936/CUSTOM_SUPPORT_IN_LIGHTSWITCH_(2)-1558057773.zip
Please let us know if you have any queries.