which event i should used to choose item from data gird view in C#

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C#2.0

C#

hi,

please help

I have 2 datagrid views.
when i come (tab focus) in 1st column, & if I press Enter then One invisible datagrid should be display. after display I can choose one of many Item list(by scrolling data gird).after enter that Item should put in 1st datagrid vies's 1st column.

i used keyUp evernt to display 2nd drid.
& for choosing item from 2nd i used cellclick. instead of cell click which event i should used?

thanks in advance.......