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Preface

I am writing a program that has a map class that contains a background image and list (ObservableCollection) of nodes that have colour, location and animation properties. A WPF application over the top has this referenced

Problem

I have an object of type GameMapModel that contains an observable collection of type GameMapNode:

 [AddINotifyPropertyChangedInterface]
public class GameMapModel

 public ObservableCollection<GameMapNode> GameMapNodes get; set; = new ObservableCollection<GameMapNode>();
 public GameMapNode SelectedNode get; set; 
 public BitmapImage Background get; set; = GameMap.jpg; //Link removed for forum post.


 public GameMapModel()
 
 //SelectedNode = new GameMapNode(0, 0, Brushes.White, "Default");
 


[AddINotifyPropertyChangedInterface]
public class GameMapNode

 public int X get; set; = 0;
 public int Y get; set; = 0;
 public Brush Colour get; set; = Brushes.Gray;
 public string Name get; set; = "Default";
 public bool Pulse get; set; = false;
 public bool Spin get; set; = false;
 public bool Throb get; set; = false;
 public bool Bounce get; set; = false;

 public GameMapNode(int x, int y, Brush colour, String name)
 
 X = x;
 Y = y;
 //Colour = colour;
 Name = name;
 

 public void ChangeTeam()
 
 if (Colour == Brushes.Blue)
 
 Colour = Brushes.Red;
 Spin = true;
 Bounce = true;
 Pulse = true;
 Throb = true;
 
 else
 
 Colour = Brushes.Blue;
 Spin = false;
 Bounce = false;
 Pulse = false;
 Throb = false;
 
 

I am then have a UserControl that renders the map background and nodes based on the contents of the GameMapModel:

 <Grid Grid.Column="1" Name="MapGrid" MouseMove="Grid_MouseMove" MouseUp="Grid_MouseUp" Width="Binding GameMap.Background.Width" Height="Binding GameMap.Background.Height" Background="Black">
 <Image Source="Binding GameMap.Background" Stretch="Fill"/>

 <ItemsControl ItemsSource="Binding GameMap.GameMapNodes">

 <ItemsControl.ItemsPanel>
 <ItemsPanelTemplate>
 <Canvas Name="MapCanvas" Width="Binding Background.Width" Height="Binding Background.Height" MinHeight="240" MinWidth="320" IsItemsHost="True"/>
 </ItemsPanelTemplate>
 </ItemsControl.ItemsPanel>

 <ItemsControl.ItemContainerStyle>
 <Style TargetType="ContentPresenter">
 <Setter Property="Canvas.Left" Value="Binding X" />
 <Setter Property="Canvas.Top" Value="Binding Y" />
 <Setter Property="ContentTemplate">
 <Setter.Value>
 <DataTemplate>
 <Grid>
 <!-- <Rectangle x:Name="rect2" Stroke="Binding GameMap.Colour" StrokeThickness="20" Width="10" Height="10" /> -->

 <Rectangle x:Name="rect1" Stroke="Binding Colour" MouseRightButtonDown="Rectangle_MouseRightButtonDown" MouseLeftButtonDown="Rectangle_MouseLeftButtonDown" StrokeThickness="20" Width="10" Height="10">

 <Rectangle.RenderTransform>
 <TransformGroup>
 <RotateTransform x:Name="noFreeze" CenterX="5" CenterY="5"/>
 <TranslateTransform x:Name="noFreeze2" />
 <ScaleTransform x:Name="NoFreeze3" CenterX="5" CenterY="5"/>
 </TransformGroup>
 </Rectangle.RenderTransform>

 <Rectangle.Style >
 <Style TargetType="Rectangle" x:Name="RectangleStyle">
 <Style.Triggers>

 <DataTrigger Binding="Binding Pulse" Value="True" x:Name="PulseDataTrigger">
 <DataTrigger.EnterActions>
 <BeginStoryboard x:Name="PulseAnimation">
 <Storyboard>
 <DoubleAnimation Storyboard.TargetProperty="Opacity" To="0.5" Duration="0:0:1" RepeatBehavior="Forever" AutoReverse="True"/>
 </Storyboard>
 </BeginStoryboard>
 </DataTrigger.EnterActions>
 <DataTrigger.ExitActions>
 <StopStoryboard BeginStoryboardName="PulseAnimation"/>
 </DataTrigger.ExitActions>
 </DataTrigger>

 <DataTrigger Binding="Binding Spin" Value="True">
 <DataTrigger.EnterActions>
 <BeginStoryboard x:Name="SpinAnimation">
 <Storyboard>
 <DoubleAnimation Storyboard.TargetProperty="(Rectangle.RenderTransform).(TransformGroup.Children)[0].(RotateTransform.Angle)" To="-360" Duration="0:0:4" RepeatBehavior="Forever" />
 </Storyboard>
 </BeginStoryboard>
 </DataTrigger.EnterActions>
 <DataTrigger.ExitActions>
 <StopStoryboard BeginStoryboardName="SpinAnimation"/>
 </DataTrigger.ExitActions>
 </DataTrigger>

 <DataTrigger Binding="Binding Bounce" Value="True">
 <DataTrigger.EnterActions>
 <BeginStoryboard x:Name="BounceAnimation">
 <Storyboard>
 <DoubleAnimation Storyboard.TargetProperty="(Rectangle.RenderTransform).(TransformGroup.Children)[1].(TranslateTransform.Y)" From="5" To="-5" Duration="0:0:1" RepeatBehavior="Forever" AutoReverse="True"/>
 </Storyboard>
 </BeginStoryboard>
 </DataTrigger.EnterActions>
 <DataTrigger.ExitActions>
 <StopStoryboard BeginStoryboardName="BounceAnimation"/>
 </DataTrigger.ExitActions>
 </DataTrigger>

 <DataTrigger Binding="Binding Throb" Value="True">
 <DataTrigger.EnterActions>
 <BeginStoryboard x:Name="ThrobAnimation">
 <Storyboard>
 <DoubleAnimation Storyboard.TargetProperty="(Rectangle.RenderTransform).(TransformGroup.Children)[2].(ScaleTransform.ScaleX)" From="1" To="2" Duration="0:0:1" RepeatBehavior="Forever" AutoReverse="True"/>
 <DoubleAnimation Storyboard.TargetProperty="(Rectangle.RenderTransform).(TransformGroup.Children)[2].(ScaleTransform.ScaleY)" From="1" To="2" Duration="0:0:1" RepeatBehavior="Forever" AutoReverse="True"/>
 </Storyboard>
 </BeginStoryboard>
 </DataTrigger.EnterActions>
 <DataTrigger.ExitActions>
 <StopStoryboard BeginStoryboardName="ThrobAnimation"/>
 </DataTrigger.ExitActions>
 </DataTrigger>

 </Style.Triggers>
 </Style>
 </Rectangle.Style>
 </Rectangle>
 </Grid>
 </DataTemplate>
 </Setter.Value>
 </Setter>
 </Style>
 </ItemsControl.ItemContainerStyle>
 </ItemsControl>
 </Grid>

Now all this works fine IF Spin, Bounce and Throb are false when I create a new instance of GameMapNode and add to the collection, after that, I can set any and all to true and animations work as expected.

If I set any of those 3 to be true during object creation then I get the following error and the program crashes:

System.Windows.Markup.XamlParseException: ''[Unknown]' property does not point to a DependencyObject in path '(0).(1)[0].(2)'.'

If I comment out the Spin/Throb/Bounce DoubleAnimation blocks of the XAML, then the animations don't work, but the program doesn't crash.

The same is NOT true for the Opacity animation which works fine, even if Pulse is set to true during object creation.

This makes me think it's something to do with TransformGroup implementation as this is NOT used for the pulse. Maybe they're not loaded before the DataTrigger is first tried?

This is my first real WPF application and I have a great mentor helping me through it, but even he's stumped. Any help of suggestions would be greatly appreciated :)