Accessing named controls from page resources - windows-runtime

Question

I needed to access to the ActualWidth of a Border that didn't have a specified Width. I have been told that I can't do that on WinRT so I used a proxy from Florian-Gl (from here).
The thing is that I need to create that proxy on the page's resource like this:
<Page.Resources>
<utils:ActualSizePropertyProxy Element="{Binding ElementName=noteBorder}" x:Name="proxy" />
</Page.Resources>
The problem is that I don't have access to that noteBorder element from the resources, but I have access to pageRoot that is the Page itself.
I guess that I can play with ElementName / Path to get access to noteBorder.
But there is some curious stuff:
The structure is something like:
Page (pageRoot) > Grid > ListView > ListView.ItemTemplate > Grid > Border (noteBorder)
So, If I create the proxy at the same level of the border, It won't run but If I change the ListView to a ItemsControl, it will run and works as expected.
If having it at the same level of the border I change the ElementName to pageRoot it will run at least.
So, It won't run if I put noteBorder (even when I have access to it) if I'm using a ListView, but will work on a ItemsControl, On the other hand, If I have pageRoot it works all ways.
So the question is: Is there a way to access noteBorder from resources? Or maybe a way to access it from another place but working :P

Answer 1

You should be using an Item Template --
By the time you get to
pageRoot) > Grid > ListView or Items Control
At this point in the structure, you're at the element you really want to get at, which is the container of the items that will need the border you are trying to access.
You should define an Item Template and assign the ListView's (or ItemsControl's) ItemTemplate property via binding.
<ListView x:Name="myListView" DataContext="{Binding ToElementIfNotInheritedFromParent}" ItemsSource="{Binding ViewModelListBeingBoundTo}" ItemTemplate="{Binding Source={Static Resource MyCustomItemTemplate}}" />
Where MyCustomItemTemplate is something like
<DataTemplate x:Name="MyCustomItemTemplate">
<Border x:Name="myBorder" >
<StackPanel>
<TextBlock Text="{Binding Path=Title}" />
<TextBlock Text="{Binding Path=FirstProperty}"/>
<TextBlock Text="{Binding Path=SecondProperty}"/>
</StackPanel>
</Border>
</DataTemplate>
Then In your Codebehind (or if ViewModel use the code behind to pass the ListView object to the ViewModel)
DataTemplate dt = this.myListView.Items[indexOfChoice].ItemTemplate as DataTemplate;
Border b = dt.LoadContent() as Border;
int actualWidth = b.AcutalWidth
OR
You can create a FindControl() method that runs recursively to extract the actual control within the border, for instance if you wanted to access one of the Textboxes.
The code for that is here:
http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/a612f5a6-e05e-4b68-a813-893eeda159cc