How can I change the font size of a label in my ControlTemplate

Question

In my WPF ListBox, I have a style with a ControlTemplate for a ListBoxItem. Inside that ControlTemplate I have a label defined. Based on some details, I need to change the font size of the label. So from my code-behind, I need to determine what the font should be and then I need to set it.

Here is my style with the ControlTemplate (I've stripped out some irrelevant controls)

<Style x:Key="RecordTabList" TargetType="{x:Type ListBoxItem}">
            <Setter Property="Background" Value="{DynamicResource RecordIndexTabBackcolor}" />
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate>        
                            <Label
                                x:Name="myLabel" Grid.Column="0" Grid.ColumnSpan="1" Grid.Row="0" Grid.RowSpan="1" Margin="3,-2,0,-2" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Foreground="{DynamicResource RecordIndexTabForeground}" 
                                FontSize="10" Height="Auto" BorderThickness="3,0,0,0"
                                Content="{Binding Path=Name}" />
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>

How can I do this?

Answer 1

If I understand you correctly, you can probably do something similar to the following, and simply change the FontSize property on the ListBoxItem itself; it will be reflected automatically on your Label. Copy this into VS and see it in action!

<Window.Resources>
    <Style TargetType="ListBoxItem">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ListBoxItem">
                    <Label Content="{TemplateBinding Content}" FontSize="{TemplateBinding FontSize}"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Window.Resources>
<Grid>
    <ListBox Margin="12">
        <ListBoxItem Content="Test 1" FontSize="14"/>
        <ListBoxItem Content="Test 2" FontSize="18"/>
        <ListBoxItem Content="Test 3" FontSize="22"/>
    </ListBox>
</Grid>

Answer 2

You might be able to use a ValueConverter on the FontSize property.. but I'm not 100% sure if they work inside a ControlTemplate.. I seem to remember Silverlight having issues with it, but I can't remember if it worked in WPF.

Answer 3

If you want to set the FontSize in the code behind, you should remove FontSize from the ControlTemplate, then set it for the ListBoxItem in the code-behind. If you want to set the same size for all the ListBoxItems just set the FontSize of the ListBox in the code-behind.