How do I apply styles to different `TextBlock` objects? - wpf

Question

Here is my Application ResourceDictionary
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:CABI_PO_Manager.Themes">
<Style TargetType="TextBlock">
<Setter Property="HorizontalAlignment" Value="Center" />
<Setter Property="FontFamily" Value="Comic Sans MS"/>
<Setter Property="FontSize" Value="14"/>
</Style>
<Style BasedOn="{StaticResource {x:Type TextBlock}}"
TargetType="TextBlock"
x:Key="YellowTextBlock">
<Setter Property="FontSize" Value="16"/>
<Setter Property="Foreground" Value="#d8b243"/>
</Style>
<Style BasedOn="{StaticResource {x:Type TextBlock}}"
TargetType="TextBlock"
x:Key="GreenTextBlock">
<Setter Property="FontSize" Value="18"/>
<Setter Property="Foreground" Value="Green"/>
</Style>
<Style BasedOn="{StaticResource {x:Type TextBlock}}"
TargetType="TextBlock"
x:Key="RedTextBlock">
<Setter Property="FontSize" Value="14"/>
<Setter Property="Foreground" Value="#a01e21"/>
</Style>
</ResourceDictionary>
I want to have some default styles for a TextBlock which works
<Style TargetType="TextBlock">
<Setter Property="HorizontalAlignment" Value="Center" />
<Setter Property="FontFamily" Value="Comic Sans MS"/>
<Setter Property="FontSize" Value="14"/>
</Style>
I found somewhere to use x:Key but I can't get it to work.
I will have several TextBlock's, How do I identify a TextBlock in the UI XAML as Red, Yellow or Green TextBlock and apply that style to them? This isn't recognized x:Key="GreenTextBlock"
<TextBlock x:Key="GreenTextBlock" Grid.Column="1" Margin="0,10,0,0" TextWrapping="Wrap" Text="PO Manager" VerticalAlignment="Top" TextAlignment="Center" FontWeight="ExtraBold"/>

Answer 1

If u want apply style on for example all TextBlocks in application, just use style without x:key defined e.g
<Style TargetType="{x:Type TextBlock}">
<Setter Property="HorizontalAlignment" Value="Center" />
<Setter Property="FontFamily" Value="Comic Sans MS"/>
<Setter Property="FontSize" Value="14"/>
</Style>
When you are applying a style, use TargetType="{x:Type TextBlock}" instead of TargetType="TextBlock"
When do you use want to base on other style use
BasedOn="{StaticResource StyleUWantToBaseOn}"
where StyleUWantToBaseOn is style with x:Key property
And when you want to apply a specific style on lets say textblock you want to use Style property e.g:
<TextBlock Style="{StaticResource GreenTextBlock}" Grid.Column="1" />