Specifying PropertyPath syntax for animation inside GroupStyle.HeaderTemplate - wpf

Question

I'm trying to perform a rotate animation inside a GroupStyle header on a DataGrid and I cannot get the PropertyPath syntax down for the Storyboard.TargetProperty property. Here's a contained example to highlight my problem
<Window x:Class="ImageRotateTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<x:Array Type="sys:String">
<sys:String>One</sys:String>
<sys:String>One</sys:String>
<sys:String>Three</sys:String>
<sys:String>Four</sys:String>
<sys:String>Four</sys:String>
</x:Array>
</Window.DataContext>
<Window.Resources>
<CollectionViewSource Source="{Binding}" x:Key="ViewSource">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription></PropertyGroupDescription>
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
</Window.Resources>
<DataGrid ItemsSource="{Binding Source={StaticResource ViewSource}}" AutoGenerateColumns="False">
<DataGrid.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}">
<TextBlock.RenderTransform>
<RotateTransform/>
</TextBlock.RenderTransform>
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding Name}" Value="Three">
<DataTrigger.EnterActions>
<BeginStoryboard x:Name="Test">
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="RenderTransform.Angle" To="360" Duration="0:0:0.800" RepeatBehavior="Forever"/>
</Storyboard>
</BeginStoryboard>
</DataTrigger.EnterActions>
<DataTrigger.ExitActions>
<StopStoryboard BeginStoryboardName="Test" />
</DataTrigger.ExitActions>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</DataGrid.GroupStyle>
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding}" Header="Item" />
</DataGrid.Columns>
</DataGrid>
The result here should be that the group header should spin only for the "Three" group and not any others. However, running this results in the following exception
A first chance exception of type 'System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll
Additional information: Cannot resolve all property references in the property path 'RenderTransform.Angle'. Verify that applicable objects support the properties.
I have tried the following for the Storyboard.TargetProperty without success
(TextBlock.RenderTransform).(RotateTransform.Angle)
(RenderTransform).(Angle)
RenderTransform.Angle
My question is; How can I refer to the TextBlock.RenderTransform using property path syntax?

Answer 1

Your code very nearly works as it is. You just need to make one change:
Storyboard.TargetProperty="RenderTransform.(RotateTransform.Angle)"
I have tested it with just the TextBlock and can see that spinning away, so if you can't see it spinning in your DataGrid, either your Name property Binding is incorrect, or its value is not the expected "Three".
<TextBlock Text="{Binding Name}">
<TextBlock.RenderTransform>
<RotateTransform/>
</TextBlock.RenderTransform>
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding Name}" Value="Three">
<DataTrigger.EnterActions>
<BeginStoryboard x:Name="Test">
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="
RenderTransform.(RotateTransform.Angle)" To="360"
Duration="0:0:0.800" RepeatBehavior="Forever"/>
</Storyboard>
</BeginStoryboard>
</DataTrigger.EnterActions>
<DataTrigger.ExitActions>
<StopStoryboard BeginStoryboardName="Test" />
</DataTrigger.ExitActions>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>

Answer 2

For Rotation of Object this is simple and best example..
<Window x:Class="Animation.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Animated Rectangle" Height="350" Width="525">
<Grid>
<StackPanel Margin="10">
<Image Name="MyImage" Source="e:\a.jpg" Width="100" Margin="50" ></Image>
<Rectangle
Name="MyRectangle"
Width="100"
Height="100"
Fill="Blue">
<Rectangle.Triggers>
<!-- Animates the rectangle's opacity. -->
<EventTrigger RoutedEvent="Rectangle.Loaded">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation
Storyboard.TargetName="MyImage"
Storyboard.TargetProperty="Opacity"
From="1.0" To="0.0" Duration="0:0:3"
AutoReverse="True" RepeatBehavior="Forever" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Rectangle.Triggers>
</Rectangle>
</StackPanel>
</Grid>