ListView: define ItemsPanelTemplate in resource dictionary

Question

I have a ListView which layout looks like a Windows Explorer view (icon + some details), bound to a list somewhere in the ViewModel.

My aim here is to be able to switch between explorer view or classic view whenever we want.

I could define an ItemsPanelTemplate doing exactly the work to display correctly the layout, directly in the ListView.ItemsPanel field. Now, I'd like to define it in the resources so that I'll be able to use it in different views, and especially in one control, the user should have the choice between Explorer view or classic list view (the default rendering for a list)

How'd you do that? I cannot define any ItemsPanelTemplate in my ResourceDictionary, and if I define a DataTemplate it is not compatible (while I thought that following pure logic, ItemsPanelTemplate should inherit from DataTemplate, but it actually doesn't look like so).

Code snippet for the actual list:

<ListView.ItemsPanel>
    <ItemsPanelTemplate>
        <WrapPanel
            Width="{Binding (FrameworkElement.ActualWidth),
                RelativeSource={RelativeSource 
                AncestorType=ScrollContentPresenter}}"
            ItemWidth="{Binding (ListView.View).ItemWidth,
                RelativeSource={RelativeSource AncestorType=ListView}}"
            ItemHeight="{Binding (ListView.View).ItemHeight,
                RelativeSource={RelativeSource AncestorType=ListView}}" 
            />
            <!--
            MinWidth="{Binding ItemWidth, RelativeSource={RelativeSource Self}}"
            -->
    </ItemsPanelTemplate>
</ListView.ItemsPanel>

<ListView.ItemTemplate>
    <DataTemplate>
        <StackPanel
            Orientation="Horizontal" 
            Height="Auto" 
            Width="150" >
            <Image 
                Source="{Binding Path=Appli.AppType, Converter={StaticResource TypeToIconConverter}}"
                Margin="5"
                Height="50"
                Width="50" />
            <StackPanel 
                VerticalAlignment="Center"
                Width="90" >
                <TextBlock 
                    Text="{Binding Path=Appli.AppName}" 
                    FontSize="13" 
                    HorizontalAlignment="Left" 
                    TextWrapping="WrapWithOverflow"
                    Margin="0,0,0,1" />
                <TextBlock 
                    Text="{Binding Path=Appli.AppType}" 
                    FontSize="9" 
                    HorizontalAlignment="Left" 
                    Margin="0,0,0,1" />
            </StackPanel>
        </StackPanel>
    </DataTemplate>
</ListView.ItemTemplate>

Keeping the ItemTemplate in a static resource was easy to do, but now I can't do anything with the ItemsPanelTemplate...

Any ideas? I'm using MVVM so I'm trying ideally not to use code-behind if possible

Letters

Answer 1

You would use a style for the whole ListView for that. So you would do:

<Grid.Resources>
    <Style x:Key="ListViewStyle" TargetType="ListView">
        <Setter Property="ItemsPanel">
            <Setter.Value>
                <ItemsPanelTemplate>
                    <WrapPanel 
                        Width="{Binding (FrameworkElement.ActualWidth), RelativeSource={RelativeSource AncestorType=ScrollContentPresenter}}"
                        ItemWidth="{Binding (ListView.View).ItemWidth, RelativeSource={RelativeSource AncestorType=ListView}}"
                        ItemHeight="{Binding (ListView.View).ItemHeight, RelativeSource={RelativeSource AncestorType=ListView}}" />
                        <!-- 
                        MinWidth="{Binding ItemWidth, RelativeSource={RelativeSource Self}}" 
                        -->
                </ItemsPanelTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Grid.Resources>

<ListView
    SelectionMode="Single"
    VerticalAlignment="Stretch"
    HorizontalAlignment="Stretch"
    HorizontalContentAlignment="Center"
    VerticalContentAlignment="Bottom"
    ScrollViewer.VerticalScrollBarVisibility="Auto"
    ItemsSource="{Binding ListUserApps, UpdateSourceTrigger=PropertyChanged}"
    SelectedIndex="{Binding SelectedUserApp, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
    Background="White"
    Style="{StaticResource ListViewStyle}">

    <ListView.ItemTemplate>
        <DataTemplate>
            <StackPanel
                Orientation="Horizontal"
                Height="Auto"
                Width="150">
                <Image
                    Source="{Binding Path=Appli.AppType, Converter={StaticResource TypeToIconConverter}}"
                    Margin="5"
                    Height="50"
                    Width="50"/>
                <StackPanel
                    VerticalAlignment="Center"
                    Width="90">

                    <TextBlock
                        Text="{Binding Path=Appli.AppName}"
                        FontSize="13"
                        HorizontalAlignment="Left"
                        TextWrapping="WrapWithOverflow"
                        Margin="0,0,0,1" />
                    <TextBlock
                        Text="{Binding Path=Appli.AppType}"
                        FontSize="9"
                        HorizontalAlignment="Left"
                        Margin="0,0,0,1" />

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

</ListView>

If you want the user then be able to switch between explorer and classic view, just define a second Style and switch the style of the listview. This can be done for example with some VisualStates and a 'DataStateBehavior'.

Alternatively you could create a style with some DataTriggers and Setters for the individual ItemsPanels.

Torp

Awesome, thanks, can't believe I haven't thought about styling the whole ListView. Guess I'll take a look at DataStateBehavior then. Thanks again – Letters

Another related question: I can't figure out how to define the ListView.GroupStyle in a predefined style. It is supposed to be a read-only property and I don't get how to define it. Any idea? – Letters