Extend ListViewItem when selected - wpf

Question

I have this ListViewItem trigger:
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsMouseOver}" Value="True" />
<Condition Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsSelected}" Value="True" />
</MultiDataTrigger.Conditions>
<Setter Property="Foreground" Value="Gray"/>
<Setter Property="Background" Value="White"/>
<Setter Property="Height" Value="50"/>
</MultiDataTrigger>
When I am selecting my ListViewItem, this item becomes larger so I can show another elements.
Now I want to implement a behavior that after each click on a ListViewItem this item will change from selected to not selected, so after each click my ListViewItem changes its height to 50 and after another click back to 22 (the default size).
I subscribed to an PreviewMouseLeftButtonDown event:
private void listView_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
}
My question is: what do I need to write into this event handler?

Answer 1

You could handle the PreviewMouseLeftButtonDown event for the ListViewItem container:
<ListView x:Name="listView">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<EventSetter Event="PreviewMouseLeftButtonDown" Handler="ListViewItem_PreviewMouseLeftButtonDown" />
<Style.Triggers>
<MultiDataTrigger>
...
</MultiDataTrigger>
</Style.Triggers>
</Style>
</ListView.ItemContainerStyle>
</ListView>
...something like this:
private void ListViewItem_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
ListViewItem lvi = (ListViewItem)sender;
if (lvi.IsSelected)
{
listView.SelectedItems.Remove(lvi.DataContext);
e.Handled = true;
}
}
I put this EventSetter after my Style (this style is in another file) and got this: 'ResourceDictionary' root element requires a x:Class attribute to support event handlers in the XAML file ...
If you define the ItemContainerStyle in a ResourceDictionary, you need to add a code-behind file to the ResourceDictionary. This is an easy thing to do:
Is it possible to set code behind a resource dictionary in WPF for event handling?
The other option would be to define the Style with the EventSetter inline in your view and base it on the Style with the MultiDataTrigger that you have defined in the ResourceDictionary:
<ListView x:Name="listView">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem" BasedOn="{StaticResource YourOtherStyleInTheResourceDictionary}">
<EventSetter Event="PreviewMouseLeftButtonDown" Handler="ListViewItem_PreviewMouseLeftButtonDown" />
</Style>
</ListView.ItemContainerStyle>
</ListView>