<string /> value from javascript

Hi,

I use

<Text Value="{Page TopBarTitle}" />

For the title in my top bar. I assign the value with

<string ux:Key="TopBarTitle" ux:Value="The Title"/>

And it works fine, but some of my pages don’t have a fixed title (news, and other cases, fact is I don’t know what it will be )

I wonder if there is a way to set the title from those pages because when I do

<string ux:Key="TopBarTitle" ux:Value="{LoadedPage.title}"/>

It shows {LoadedPage.title}