RelativeSource FindAncestor, AncestorType='System.Windows.Controls.Expander', AncestorLevel='1'

[liuyafei518]

Bug explanation

why my app show bind error ？
this is Error description:
bindPath: ExpandDirection
target: RotateTransform.Angle
description: Unable to find resources: RelativeSource FindAncestor, AncestorType='System.Windows.Controls.Expander', AncestorLevel='1'

this is my code :

<ListBox.ItemTemplate>
    <DataTemplate>
        <StackPanel
            HorizontalAlignment="Stretch"
            Background="Transparent"
            Orientation="Horizontal"
            PreviewMouseDown="StackPanel_PreviewMouseDown">
            <StackPanel
                Margin="25,10,0,10"
                Orientation="Horizontal"
                Visibility="{Binding IsShowParentMenu, Converter={StaticResource Boolean2VisibilityConverter}}">
                <materialDesign:PackIcon
                    Width="24"
                    Height="24"
                    Margin="0,0,5,0"
                    Foreground="White"
                    Kind="{Binding Icon}" />
                <TextBlock
                    Margin="10,0,10,0"
                    HorizontalAlignment="Left"
                    VerticalAlignment="Center"
                    FontSize="14"
                    FontWeight="Bold"
                    Foreground="White"
                    Text="{Binding Header}" />
            </StackPanel>
            <Expander
                x:Name="ExpanderMenu"
                Width="230"
                Margin="5,2,5,2"
                HorizontalAlignment="Center"
                Background="{x:Null}"
                ExpandDirection="Down"
                Foreground="White"
                IsExpanded="False"
                materialDesign:TransitionAssist.DisableTransitions="True"
                Visibility="{Binding HasChild, Converter={StaticResource Boolean2VisibilityConverter}}">

                <Expander.Header>
                    <StackPanel x:Name="ExpandHeader" Orientation="Horizontal">
                        <materialDesign:PackIcon
                            Width="24"
                            Height="24"
                            Margin="0,0,5,0"
                            Foreground="White"
                            Kind="{Binding Icon}" />
                        <TextBlock
                            Margin="10,0,10,0"
                            HorizontalAlignment="Left"
                            VerticalAlignment="Center"
                            FontSize="14"
                            FontWeight="Bold"
                            Foreground="White"
                            Text="{Binding Header}" />
                    </StackPanel>

                </Expander.Header>
                <ListView
                    x:Name="ListViewMenu"
                    Foreground="White"
                    ItemsSource="{Binding SubItems}"
                    ScrollViewer.HorizontalScrollBarVisibility="Disabled"
                    SelectionChanged="ListViewMenu_SelectionChanged">
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <StackPanel
                                x:Name="subItemPanel"
                                Margin="18,0,0,0"
                                Orientation="Horizontal">
                                <materialDesign:PackIcon
                                    Width="20"
                                    Height="20"
                                    Margin="0,0,10,0"
                                    VerticalAlignment="Center"
                                    Foreground="White"
                                    Kind="{Binding Icon}" />
                                <TextBlock
                                    Padding="5"
                                    VerticalAlignment="Center"
                                    FontSize="14"
                                    Text="{Binding Header}" />
                            </StackPanel>

                        </DataTemplate>
                    </ListView.ItemTemplate>
                </ListView>
            </Expander>
        </StackPanel>
    </DataTemplate>
</ListBox.ItemTemplate>

Version

5.2.1