MVC3 - search form validation via data annotations

Hi, i have a search form on which i have text boxes, check boxes and drop down. I am already checking email and valid dates.

On form submit, i want to make sure that atleast one item is selected. How can i do this best using data annotations?

I think somebody might have written a custom validator to handle this scenario already, but the name isn’t jumping out at me. In any case, it is probably doable with a custom validator and alot of code, but I would just write a little javascript and integrate it that way as these sorts of scenarios are pretty ugly with data annotations. Unless you like writing reflection code.

I already have a jquery soution in place. Its fully dynamic and works for me.