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POListBox with Grid as ItemsPanelTemplate produces weird binding errors
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  1. POListBox with Grid as ItemsPanelTemplate produces weird binding errors
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    copied!<p>I've got a ListBox control and I'm presenting a fixed number of ListBoxItem objects in a grid layout. So I've set my ItemsPanelTemplate to be a Grid.</p> <p>I'm accessing the Grid from code behind to configure the RowDefinitions and ColumnDefinitions.</p> <p>So far it's all working as I expect. I've got some custom IValueConverter implementations for returning the Grid.Row and Grid.Column that each ListBoxItem should appear in.</p> <p>However I get weird binding errors sometimes, and I can't figure out exactly why they're happening, or even if they're in my code.</p> <p>Here's the error I get:</p> <blockquote> <p><code>System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. BindingExpression:Path=HorizontalContentAlignment; DataItem=null; target element is 'ListBoxItem' (Name=''); target property is 'HorizontalContentAlignment' (type 'HorizontalAlignment')</code></p> </blockquote> <p>Can anybody explain what's going on?</p> <p>Oh, and, here's my XAML:</p> <pre><code>&lt;UserControl.Resources&gt; &lt;!-- Value Converters --&gt; &lt;v:GridRowConverter x:Key="GridRowConverter" /&gt; &lt;v:GridColumnConverter x:Key="GridColumnConverter" /&gt; &lt;v:DevicePositionConverter x:Key="DevicePositionConverter" /&gt; &lt;v:DeviceBackgroundConverter x:Key="DeviceBackgroundConverter" /&gt; &lt;Style x:Key="DeviceContainerStyle" TargetType="{x:Type ListBoxItem}"&gt; &lt;Setter Property="FocusVisualStyle" Value="{x:Null}" /&gt; &lt;Setter Property="Background" Value="Transparent" /&gt; &lt;Setter Property="Grid.Row" Value="{Binding Path=DeviceId, Converter={StaticResource GridRowConverter}}" /&gt; &lt;Setter Property="Grid.Column" Value="{Binding Path=DeviceId, Converter={StaticResource GridColumnConverter}}" /&gt; &lt;Setter Property="Template"&gt; &lt;Setter.Value&gt; &lt;ControlTemplate TargetType="{x:Type ListBoxItem}"&gt; &lt;Border CornerRadius="2" BorderThickness="1" BorderBrush="White" Margin="2" Name="Bd" Background="{Binding Converter={StaticResource DeviceBackgroundConverter}}"&gt; &lt;TextBlock FontSize="12" HorizontalAlignment="Center" VerticalAlignment="Center" Text="{Binding Path=DeviceId, Converter={StaticResource DevicePositionConverter}}" &gt; &lt;TextBlock.LayoutTransform&gt; &lt;RotateTransform Angle="270" /&gt; &lt;/TextBlock.LayoutTransform&gt; &lt;/TextBlock&gt; &lt;/Border&gt; &lt;ControlTemplate.Triggers&gt; &lt;Trigger Property="IsSelected" Value="true"&gt; &lt;Setter TargetName="Bd" Property="BorderThickness" Value="2" /&gt; &lt;Setter TargetName="Bd" Property="Margin" Value="1" /&gt; &lt;/Trigger&gt; &lt;/ControlTemplate.Triggers&gt; &lt;/ControlTemplate&gt; &lt;/Setter.Value&gt; &lt;/Setter&gt; &lt;/Style&gt; &lt;/UserControl.Resources&gt; &lt;Border CornerRadius="3" BorderThickness="3" Background="#FF333333" BorderBrush="#FF333333" &gt; &lt;Grid ShowGridLines="False"&gt; &lt;Grid.RowDefinitions&gt; &lt;RowDefinition Height="15" /&gt; &lt;RowDefinition Height="*" /&gt; &lt;/Grid.RowDefinitions&gt; &lt;StackPanel Grid.Row="0" Orientation="Horizontal"&gt; &lt;Image Margin="20,3,3,3" Source="Barcode.GIF" Width="60" Stretch="Fill" /&gt; &lt;/StackPanel&gt; &lt;ListBox ItemsSource="{Binding}" x:Name="lstDevices" Grid.Row="1" ItemContainerStyle="{StaticResource DeviceContainerStyle}" Background="#FF333333" SelectedItem="{Binding SelectedDeviceResult, ElementName=root, Mode=TwoWay}" &gt; &lt;ListBox.ItemsPanel&gt; &lt;ItemsPanelTemplate&gt; &lt;Grid&gt; &lt;Grid.LayoutTransform&gt; &lt;RotateTransform Angle="90" /&gt; &lt;/Grid.LayoutTransform&gt; &lt;/Grid&gt; &lt;/ItemsPanelTemplate&gt; &lt;/ListBox.ItemsPanel&gt; &lt;/ListBox&gt; &lt;/Grid&gt; &lt;/Border&gt; </code></pre> <p></p>
 

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