WPF XAML: How to automatically scale down children of a component in XAML?

Question

Here's my problem:

xaml file 1: a templated list control

<ItemsControl ItemSource={Binding myUIrelatedDataList}/>
   <ItemsControl.ItemTemplate>
       <DataTemplate>
           <my:DynamicUIPresenter Width="160" Height="80"/>
           <!-- here, I want to specify my desired size to which i want to
                scale down the generated UIElements -->
       </DataTemplate>
   </ItemsControl.ItemTemplate>
<ItemsControl/>

xaml file 2: the item template

 <Border BorderBrush="Black" BorderThickness="1">
    <Border Child="{Binding Path=., Converter={StaticResource DynaUIConverter}}"/>
 </Border>

The problem is that I do not know anything about the myUIrelatedDataList and what exact kind of UIElements the DynaUIConverter is producing. The DynaUIConverter usually produces a set of Stackpanels nested in each other and containing TextBoxes, Buttons, etc. These panels do not have a Width or Height set, which I might not be able to fix.

I think I need to measure the minimum size requirements of the generated UI and dynamically apply a ScaleTransform to the produced UI, or maybe better to the Border containing the generated UI.

I tried this in code behind, but the scaling did not work correctly, since I was not able to understand how/if width and height propagation from children to parents really works. And I also ran into some recursion problem, which made the code in the end quite inefficient.

The Question now is: Can I do this downscaling of a child element directly/easily in XAML?

Answer 1

Yeah Set VerticalStretch for your repeating element to Stretch, that should automatically make them behave as part of the list.

As for the list, if it blows out of your container, put it in a Dockpanel.

Sorry I couldn't understand what you're doing with the scale transform :) ... but it does sound like hammering a screw in.

Maybe post a screenshot if that doesn't do it to help us understand.

Answer 2

I believe a Viewbox will do what you want. It has a single child which is always given its desired size, and it applies a ScaleTransform to the child so that it fits inside the Viewbox. By default it will apply a uniform stretch, but you can change this by setting the Stretch property.

Something like this:

<ItemsControl ItemsSource="{Binding myUIrelatedDataList}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <Viewbox Width="160" Height="80">
                <my:DynamicUIPresenter />
            </Viewbox>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>