Question

Need an advice (better from your real projects) – what is the best way to do visual inheretence in WPF?

More concrete: How to inherete window view with a statusbar?

There is no way to inherete one xaml file from another. Then, are you create User Control MyStatusbar and paste it on every page?

It is possible to create Style Template for base window and use style inheretence, however this only for simple visual properties (color, size).
Second idea is to create base DataTemplate, but there is no inheritance.

P.S. In WinForms there is base Form with status bar and some logic. After adding property

public string StatusbarText {set{baseStatusbar.Text = value;}}

it is very simple to use the property in child forms. Plus we have view inheritance with status bar.

I know how to inherete logic in WPF, but what to do with visualisation.

Answer 1

You could certainly create a custom Window control that adds a StatusbarText property. Alternatively, you could use a custom Style for Window, the only question there is how to pass the status bar items into your Style. For that you can use attached properties.

If you go this route, you cannot inherit your custom Style from the default one, as you need to completely redefine the ControlTemplate. A Style for Window would look like:

<ControlTemplate x:Key="WindowTemplateKey"
                 TargetType="{x:Type Window}">
    <Border Background="{TemplateBinding Background}"
            BorderBrush="{TemplateBinding BorderBrush}"
            BorderThickness="{TemplateBinding BorderThickness}">
        <Grid>
            <AdornerDecorator>
                <DockPanel>
                    <StatusBar DockPanel.Dock="Bottom" ItemsSource="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}" />
                    <ContentPresenter/>
                </DockPanel>
            </AdornerDecorator>

            <ResizeGrip x:Name="WindowResizeGrip"
                        HorizontalAlignment="Right"
                        VerticalAlignment="Bottom"
                        Visibility="Collapsed"
                        IsTabStop="false"/>
        </Grid>
    </Border>
    <ControlTemplate.Triggers>
        <MultiTrigger>
            <MultiTrigger.Conditions>
                <Condition Property="Window.ResizeMode"
                           Value="CanResizeWithGrip"/>
                <Condition Property="Window.WindowState"
                           Value="Normal"/>
            </MultiTrigger.Conditions>
            <Setter TargetName="WindowResizeGrip"
                    Property="Visibility"
                    Value="Visible"/>
        </MultiTrigger>
    </ControlTemplate.Triggers>
</ControlTemplate>


<Style x:Key="{x:Type Window}"
       TargetType="{x:Type Window}">
    <Setter Property="Foreground"
            Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
    <Setter Property="Background"
            Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Window}">
                <Border Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}">
                    <AdornerDecorator>
                        <DockPanel>
                            <StatusBar DockPanel.Dock="Bottom" ItemsSource="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}" />
                            <ContentPresenter/>
                        </DockPanel>
                    </AdornerDecorator>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="Window.ResizeMode"
                 Value="CanResizeWithGrip">
            <Setter Property="Template"
                    Value="{StaticResource WindowTemplateKey}"/>
        </Trigger>
    </Style.Triggers>
</Style>

If you use the Style above, you can set the Window.Tag property to be a list of items you want displayed in the StatusBar. The biggest problem with this approach is you would need to add attached properties for things like StatusBar.ItemContainerStyle so you can customize the look of your status bar.

Same holds for if you use a DataTemplate. So i you know you only ever want single text in your StatusBar, you could use the following in the ControlTemplates above and set the Window.Tag to the string (or use an attached property).

<StatusBar DockPanel.Dock="Bottom">
    <StatusBarItem Content="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}" />
</StatusBar>