Insert or Update checked rows only in sql server 2008 table

Question

I have one datagridview in my windows form.. (C#.Net). The datagridview have one datagridviewcheckbox column. Nearly 100 data rows in datagridview. My question is i want to insert or update checked rows only in sql server table. for example i checked only 50 rows . so i want to insert or update 50 rows only in sql server table. Plese help me how can i do this??????????????????