detecting form opened or visible

[Maileen]

Hi,

I have a VB.NET application which includes several forms.
however,i need to know which form is opened and visible, like that i can actualize it. (typically dynamic changes of language interface).

how can i detect opened and visible forms ?

I was thinking to use my Mainform and pass through all Controls if they are forms of not, and so on...

but i miss samples :(

thanks for help.
Maileen