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POHow to save the IsExpanded state in group headers of a listview
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  1. POHow to save the IsExpanded state in group headers of a listview
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    copied!<p>I have quite a tricky problem:</p> <p>I am using a ListView control with the ItemsSource set to a CollectionViewSource including a PropertyGroupDescription to group the ListView elements. The CollectionViewSource looks like this:</p> <pre><code>&lt;CollectionViewSource x:Key="ListViewObjects"&gt; &lt;CollectionViewSource.Source&gt; &lt;Binding Path="CurrentListViewData"/&gt; &lt;/CollectionViewSource.Source&gt; &lt;CollectionViewSource.GroupDescriptions&gt; &lt;PropertyGroupDescription PropertyName="ObjectType" /&gt; &lt;/CollectionViewSource.GroupDescriptions&gt; &lt;/CollectionViewSource&gt; </code></pre> <p>In the ListView I use customize the group headers like this:</p> <pre><code>&lt;ListView.GroupStyle&gt; &lt;GroupStyle&gt; &lt;GroupStyle.ContainerStyle&gt; &lt;Style TargetType="{x:Type GroupItem}"&gt; &lt;Setter Property="Margin" Value="5"/&gt; &lt;Setter Property="Template"&gt; &lt;Setter.Value&gt; &lt;ControlTemplate TargetType="{x:Type GroupItem}"&gt; &lt;Expander IsExpanded="True"&gt; &lt;Expander.Header&gt; &lt;DockPanel&gt; &lt;TextBlock Text="{Binding Path=Items[0].ObjectType /&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; </code></pre> <p>As you can see the IsExpanded property of the Expander is set to true. This means that whenever the ListView is refreshed, all Expander controls are expanded.</p> <p>I do however want to save the last state of every Expander. I haven't been able to figure out a way to save a list of Expander states per ObjectType. I was experimenting with a bound HashTable and a Converter, but I failed at providing the ObjectType as a ConverterParameter, because it was always passed as a string. But that may not be the solution anyways.</p> <p>Can somebody give me a hint or an idea for a solution, please? :)</p>
 

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