You can have a look at this article
for two approaches on how to access the child GridViews.
Once you have access to the child GridView, you can handle its RowLoaded
event and there handle the row's double-click event.
I hope you find this helpful. Let me know if you need further assistance in implementing this.
Do you need help with upgrading your AJAX, WPF or WinForms project? Check the Telerik API Analyzer
and share your thoughts.