How to get values in a carousel in sapui5

Hi expert,

I modified the example carousel "Carousel with Multiple Items at Once" i added a input field (with an Id) and a button save. When I click on the Button the input element can't be found with the Id. I get undefined. When I check the element (with the developer tools) the id is the generated Id + my Id + the pagenr.. How can I get the input value? Is it possible what I want, or do i have to use another solution?

We use the carousel, because we want to show one item at the time.

Hope you can help me.

Thanks in advance,

Vo