Why do you need to use x:Static instead of the string value of the enum?

<TextBlock Text="Hello World"  FontSize="99" FontFamily="{StaticResource Technor}" FontWeight="Bold" />

Anyway, this is a deviation we should fix, right SergIo?

Yes, we should fix it, just trying to figure out the priority in case using the plain enum value is enough.

Heya, I was using x:Static for animation purposes :)

It's pretty easy to get around, but it adds quite a few lines

      <Storyboard x:Key="Storyboard0">
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextBlock0" Storyboard.TargetProperty="(TextElement.FontWeight)">
          <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static FontWeight.SemiLight}"/>
          <DiscreteObjectKeyFrame KeyTime="00:00:01" Value="{x:Static FontWeight.Black}"/>
        </ObjectAnimationUsingKeyFrames>
      </Storyboard>

vs

      <Storyboard x:Key="Storyboard0">
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="TextBlock0"
                                       Storyboard.TargetProperty="(TextElement.FontWeight)">
          <DiscreteObjectKeyFrame KeyTime="00:00:00">
            <DiscreteObjectKeyFrame.Value>
              <FontWeight>
                SemiLight
              </FontWeight>
            </DiscreteObjectKeyFrame.Value>
          </DiscreteObjectKeyFrame>
          <DiscreteObjectKeyFrame KeyTime="00:00:01">
            <DiscreteObjectKeyFrame.Value>
              <FontWeight>
                Black
              </FontWeight>
            </DiscreteObjectKeyFrame.Value>
          </DiscreteObjectKeyFrame>
        </ObjectAnimationUsingKeyFrames>
      </Storyboard>

Oh, I see your scenario. Although there is a way to simplify the xaml a lot by using resources, something like this:

<Grid
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid.Resources>
    <FontWeight x:Key="FWNormal">Normal</FontWeight>
    <FontWeight x:Key="FWBold">Bold</FontWeight>
    <Storyboard x:Key="Anim">
      <ObjectAnimationUsingKeyFrames Storyboard.TargetName="txt" Storyboard.TargetProperty="FontWeight">
        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource FWNormal}"/>
        <DiscreteObjectKeyFrame KeyTime="0:0:1" Value="{StaticResource FWBold}"/>
        <DiscreteObjectKeyFrame KeyTime="0:0:2" Value="{StaticResource FWNormal}"/>
      </ObjectAnimationUsingKeyFrames>
    </Storyboard>
  </Grid.Resources>
  <Grid.Triggers>
    <EventTrigger RoutedEvent="Grid.Loaded">
      <BeginStoryboard Storyboard="{StaticResource Anim}"/>
    </EventTrigger>
  </Grid.Triggers>
  <TextBlock x:Name="txt" Text="Hello World" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="30"/>
</Grid>

I can't believe I didn't even think of doing something like that - that's a great solution, thank you!