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POHow to save the IsExpanded state in group headers of a listview - Take 2
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  1. POHow to save the IsExpanded state in group headers of a listview - Take 2
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    copied!<p>To get some context this question refers to <a href="https://stackoverflow.com/questions/2808777/how-to-save-the-isexpanded-state-in-group-headers-of-a-listview/12343338#12343338">How to save the IsExpanded state in group headers of a listview</a></p> <p>What am I missing here?</p> <p>When I try to do what is suggested in the referenced post I get: </p> <p><strong>BindingExpression path error: '[]' property not found on 'object' ''ExpandStateManager'</strong></p> <p><strong>My ExpandStateManager</strong></p> <pre><code>public class ExpandStateManager { Dictionary&lt;Category, bool&gt; expandStates = new Dictionary&lt;Category, bool&gt;(); public bool this[Category key] { get { if (!expandStates.ContainsKey(key)) return false; return expandStates[key]; } set { expandStates[key] = value; } } } </code></pre> <p><strong>XAML</strong></p> <pre><code> &lt;ListView ItemsSource="{Binding Source={StaticResource cvs}}" ItemTemplate="{StaticResource animalTemplate}" Width="200"&gt; &lt;ListView.GroupStyle&gt; &lt;GroupStyle&gt; &lt;GroupStyle.ContainerStyle&gt; &lt;Style TargetType="{x:Type GroupItem}"&gt; &lt;Setter Property="Template"&gt; &lt;Setter.Value&gt; &lt;ControlTemplate TargetType="{x:Type GroupItem}"&gt; &lt;Expander IsExpanded="{Binding Source={StaticResource ExpandStateManger}, Path=[Items[0].ObjectType]}"&gt; &lt;Expander.Header&gt; &lt;DockPanel&gt; &lt;TextBlock Text="{Binding Name}" /&gt; &lt;/DockPanel&gt; &lt;/Expander.Header&gt; &lt;Expander.Content&gt; &lt;ItemsPresenter /&gt; &lt;/Expander.Content&gt; &lt;/Expander&gt; &lt;/ControlTemplate&gt; &lt;/Setter.Value&gt; &lt;/Setter&gt; &lt;/Style&gt; &lt;/GroupStyle.ContainerStyle&gt; &lt;/GroupStyle&gt; &lt;/ListView.GroupStyle&gt; &lt;/ListView&gt; </code></pre>
 

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