DataGrid - row onclick event

Hello,

I tried to add an onclick event on a row in the datagrid but couldn't
do it. I need it because I want to add some actions when the user
clicks some specific row.

I tried to just add the attribute onclick="..." in the <item> tag, but
it does not work. I also can't find any information about this in
google or in this mailing list.

Do you have some idea, how this could be done?

Greetings,
Nikolay