Are the controls all in the same container? For example, in the same Window
or StackPanel
? If so, you can make set those properties on the parent container and they'll apply to any children. For example:
<StackPanel TextBlock.FontFamily="Comic Sans"
TextBlock.FontSize="14"
TextBlock.Foreground="Purple">
<TextBlock Text="Yeah, baby! I love me some Comic Sans!" />
<Button Content="Me too!" />
</StackPanel>
If you want to standardize the font across your entire app, you can use an implict style in your App.xaml file, like this:
<Style TargetType="TextBlock">
<Setter Property="FontFamily" Value="Comic Sans" />
<Setter Property="FontSize" Value="14" />
<Setter Property="Foreground" Value="Purple" />
</Style>