使用ContentPresenter，不使用ContentControl

参考： https://wpf.2000things.com/2017/04/06/1204-using-a-datatrigger-to-change-content-in-a-contentpresenter/

<Window.Resources>
    <DataTemplate x:Key="DefaultContent">
        <StackPanel>
            <TextBlock Margin="10" Text="Some default content here.."/>
            <TextBlock Margin="10" Text="Maybe show progress for operation"/>
        </StackPanel>
    </DataTemplate>

    <DataTemplate x:Key="AllDoneContent">
        <StackPanel>
            <TextBlock Margin="10" Text="** This is the ALL DONE content..."
                       Foreground="Green"/>
            <TextBlock Margin="10" Text="Put anything you like here"/>
            <Button Margin="10" Content="Click Me" HorizontalAlignment="Left"/>
        </StackPanel>
    </DataTemplate>

    <Style x:Key="MyContentStyle" TargetType="ContentPresenter">
        <Setter Property="ContentTemplate" Value="{StaticResource DefaultContent}"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding JobDone}" Value="True">
                <Setter Property="ContentTemplate" Value="{StaticResource AllDoneContent}"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>

</Window.Resources>

<Grid Margin="10">
    <Grid.RowDefinitions>
        <RowDefinition Height="*"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>

    <ContentPresenter Grid.Row="0" Style="{StaticResource MyContentStyle}" Content="{Binding}"/>

    <Separator Grid.Row="1"/>

    <CheckBox Grid.Row="2" Margin="10" Content="Mark job done" IsChecked="{Binding JobDone}"/>
</Grid>

ContentControl通过DataTrigger进行切换模板时，原来绑定的模板会引发DataContext事件