I have developed ig grid with following features : -
Thank you for posting in our community.
In order to get the selected row when clicking the checkbox, the rowSelectionChanged event can be handled.
I have created and attached a small sample for your reference.
Please test it on your side and let me know how it behaves. If this is not an accurate demonstration of what you are trying to achieve please feel free to modify it and send it back to me.
Looking forward to hearing from you.