c# - Content of a Button Style appears only in one Button instance

Question

I have a Viewbox:

<Viewbox x:Key="SampleViewbox" >
  <Grid>
    <Ellipse Stroke="#e2e2e0" StrokeThickness="6" Fill="#d5273e" Width="128" Height="128"/>
  </Grid>
</Viewbox>

I then include this in a Style like:

<Style x:Key="SampleStyle" TargetType="{x:Type Button}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Button}">
                <Border Background="Transparent" >
                    <ContentPresenter Content="{StaticResource SampleViewbox}"/>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Now I created many buttons with SampleStyle

<Grid>   
    <StackPanel>
       <Button Style="{StaticResource SampleStyle}" Height="50" Width="50"></Button>
       <Button Style="{StaticResource SampleStyle}" Height="80" Width="80"></Button>
       <Button Style="{StaticResource SampleStyle}" Height="20" Width="20"></Button>  
    </StackPanel>
</Grid>

However, Only one button has the Ellipse (viewbox)

How can I make all the buttons have/show the ellipse??

Answer 1

Viewbox is FrameworkElement which cannot belong to multiple parents. Every time buttons request a resource {StaticResource SampleViewbox} they get the same instance.

to change that behavior add x:Shared="False" attribute

<Viewbox x:Key="SampleViewbox" x:Shared="False">