Silverlight: Invalid Attribute Type for TargetType

Question

Just playing around with Silverlight a bit and trying to set a style to apply to all TextBlocks. The following XAML:

<Style TargetType="{x:Type TextBlock}">
   <Setter Property="Margin" Value="10, 10, 10, 10" />
</Style>

Gives me the error Invalid attribute value {x:Type TextBlock} for property TargetType.

I copied and pasted this bit from the MSDN so I'm a little lost as to why I'm getting this error.

EDIT:

Here's the full code I'm attempting now:

<UserControl x:Class="NIRC.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300">
    <UserControl.Resources>
        <Style TargetType="TextBlock">
            <Setter Property="Margin" Value="10" />
            <Setter Property="Foreground" Value="Red" />
        </Style>
    </UserControl.Resources>
    <TextBlock>Hello World!</TextBlock>
</UserControl>

Here's how it looks:

alt text http://www.netortech.com/Content/slhw.jpg

Answer 1

Value of TargetType change to TextBlock only. It should work.

<Style TargetType="TextBlock">
   <Setter Property="Margin" Value="10, 10, 10, 10" />
</Style>

Optionally, give it x:Key and the value of this attribute use in your TextBlock as StaticResource.

<Style x:Key="someStyleName" TargetType="TextBlock">
   <Setter Property="Margin" Value="10, 10, 10, 10" />
</Style>
...
<TextBlock x:Name="myTextBlock" Text="Silverlight" Style="{StaticResource someStyleName}"/> 

Answer 2

Silverlight does not support implicit styling via generic Styles (i.e. with a TargetType but without a static resource key - x:Key="") but WPF does.

You need to explicitly apply Styles using StaticResource references on each instance of your element that you want styled using Style="{StaticResource stylename}".

The Silverlight toolkit has an Implicit Style Manager (ISM) that gets around this by wrapping Silverlight markup and applying styles from ResourceDictionaries by parsing the content.

Answer 3

Since what you are trying to do is implicit styling, so far Gordon's answer seems the right one: "Silverlight does not support implicit styling via generic Styles (i.e. with a TargetType but without a static resource key - x:Key="") but WPF does."

However implicit styles will work with Silverlight 4. See http://www.silverlightshow.net/items/Implicit-Styles-in-Silverlight-4.aspx

Answer 4

Hmm, the following should work and cascade to all textblocks in the usercontrol element.

<UserControl>
    <UserControl.Resources>
        <Style TargetType="TextBlock">
            <Setter Property="Margin" Value="10" />
        </Style>
    </UserControl.Resources>
    <TextBlock Text="This has a margin of 10 on all sides!" />
</UserControl>

Edit:
Is NIRC.Page the correct codebehind for the usercontrol?

I wish I knew what was wrong, the following works perfect for me in a user control.

<UserControl x:Class="..."
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="300" Width="300">
    <UserControl.Resources>
        <Style TargetType="TextBlock">
            <Setter Property="Margin" Value="10" />
            <Setter Property="Foreground" Value="Red" />
        </Style>
    </UserControl.Resources>
    <TextBlock>Hello World!</TextBlock>
</UserControl>

Result is red text with a margin of 10px on all sides.

Answer 5

Yeah, Silverlight 4 lets you do implicit styles now, you just need to do what Quinton says and just set the TargetType without a key, and you're good to go. Put it in the App.xaml and it should propogate the style to all controls in the app.

Answer 6

If you don't want to set Style each time you use your control, you can set it in your constructor code:

Style = (Style)Application.Current.Resources["YourStyle"];