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Binding Error in DrawingImage Style

<Window x:Class="Project.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="100" Height="400">

    <Window.Resources>
        <Style x:Key="IconStyle" TargetType="{x:Type Image}">
            <Setter Property="Source">
                <Setter.Value>
                    <DrawingImage>
                        <DrawingImage.Drawing>
                            <GeometryDrawing Brush="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentControl}}, Path=Foreground}">
                                <GeometryDrawing.Geometry>
                                    <PathGeometry Figures="M 0,0 0,10 10,5" />
                                </GeometryDrawing.Geometry>
                            </GeometryDrawing>
                        </DrawingImage.Drawing>
                    </DrawingImage>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <StackPanel>

        <ContentControl Foreground="Red">
            <Image Style="{StaticResource IconStyle}" />
        </ContentControl>

        <ContentControl Foreground="Blue">
            <Image Style="{StaticResource IconStyle}" />
        </ContentControl>

    </StackPanel>

</Window>

This example shows two icons. Icons have the color of the parent ContentControl. It is working fine.

But the output shows a binding error:

Error System.Windows.Data: 4: Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType =' System.Windows.Controls.ContentControl ', AncestorLevel =' 1 ''. BindingExpression: Path = foreground; DataItem = NULL; the target element is "GeometryDrawing" (HashCode = 8154127); target is "Brush" (type "Brush")

Why does this error occur? How can I fix or ignore?

EDIT

An error also occurs in this case:

<Window x:Class="Project.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="100" Height="400">

    <Window.Resources>
        <Style x:Key="IconStyle" TargetType="{x:Type ContentControl}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ContentControl">
                        <Image>
                            <Image.Source>
                                <DrawingImage>
                                    <DrawingImage.Drawing>
                                        <GeometryDrawing Brush="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentControl}}, Path=Foreground}">
                                            <GeometryDrawing.Geometry>
                                                <PathGeometry Figures="M 0,0 0,10 10,5" />
                                            </GeometryDrawing.Geometry>
                                        </GeometryDrawing>
                                    </DrawingImage.Drawing>
                                </DrawingImage>
                            </Image.Source>
                        </Image>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <StackPanel>    
        <ContentControl Foreground="Red" Style="{StaticResource IconStyle}" />    
        <ContentControl Foreground="Blue" Style="{StaticResource IconStyle}" />    
    </StackPanel>

</Window>
+4
1

:

  <GeometryDrawing x:Name="GeometryDrawing" Brush="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Foreground}">
                                        <GeometryDrawing.Geometry>
                                            <PathGeometry Figures="M 0,0 0,10 10,5" />
                                        </GeometryDrawing.Geometry>
                                    </GeometryDrawing>

Parent:

   RelativeSource={RelativeSource TemplatedParent}

EDIT:

VS,

+2

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