List box in view mode

[Nicolas na BO, módosítva 15 év-val korábban]

Hello,
I'm developing an application using liferay 4.3.0.
I want to add a listbox in the title bar in View mode which, when the user select a value, change a portlet parameter.

I add the listbox in the file portlet.vm. But I don't know how to change the paramater.

Thanks for your answers.

Nicolas