<Window x:Class="WpfApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp"
        mc:Ignorable="d"
        WindowStartupLocation="CenterScreen"
        ResizeMode="CanMinimize"
        Title="MainWindow" Height="350" Width="625">
    <Window.Resources>
        <!--直接路劲引用，单个程序集里面其实可以省略路径前面/WpfApp;component/一截-->
        <ResourceDictionary Source="/WpfApp;component/Assist/Dictionary1.xaml"/>
    </Window.Resources>

    <!--窗体内容-->
    <StackPanel Orientation="Horizontal" Margin="5">
        <UserControl ContentTemplate="{StaticResource carDetailViewTemplate}" Content="{Binding SelectedItem, ElementName=listBoxCars}"/>
        <ListBox x:Name="listBoxCars" Width="180" Margin="5 0" ItemTemplate="{StaticResource carListItemViewTemplate}"/>
    </StackPanel>
</Window>   

<ResourceDictionary Source="/WpfApp;component/Assist/Dictionary1.xaml"/> 引用的是数据模板在项目中的文件路径。和控件模板的方式差不多。

Dictionary1.xaml：

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:local="clr-namespace:WpfApp">

    <!--Converter-->
    <local:AutomakerToLogoPathConverter x:Key="a2l"/>
    <local:NameToPhotoPathConverter x:Key="n2p"/>

    <!--DataTemplate for Detail View-->
    <DataTemplate x:Key="carDetailViewTemplate">
        <Border BorderBrush="Black" BorderThickness="1" CornerRadius="6">
            <StackPanel Margin="5">
                <Image Width="400" Height="250" Stretch="Fill" Source="{Binding Name, Converter={StaticResource n2p}}"/>
                <StackPanel Orientation="Horizontal" Margin="5 0">
                    <TextBlock Text="品牌:" FontWeight="Bold" FontSize="20"/>
                    <TextBlock Text="{Binding Name}" FontSize="20" Margin="5 0"/>
                </StackPanel>
                <StackPanel Orientation="Horizontal" Margin="5 0">
                    <TextBlock Text="制造商：" FontWeight="Bold"/>
                    <TextBlock Text="{Binding Automaker}" />
                    <TextBlock Text="年份：" FontWeight="Bold" Margin="10 0 0 0"/>
                    <TextBlock Text="{Binding Year}" />
                    <TextBlock Text="最高速度：" FontWeight="Bold" Margin="10 0 0 0"/>
                    <TextBlock Text="{Binding TopSpeed, StringFormat={}{0}Km/h}" />
                </StackPanel>
            </StackPanel>
        </Border>
    </DataTemplate>

    <!--DataTemplate for Item View-->
    <DataTemplate x:Key="carListItemViewTemplate">
        <Grid Margin="2">
            <StackPanel Orientation="Horizontal">
                <Image Source="{Binding Automaker, Converter={StaticResource a2l}}" Grid.RowSpan="3"  Width="64" Height="64"/>
                <StackPanel Margin="5 10">
                    <TextBlock Text="{Binding Name}" FontSize="16" FontWeight="Bold"/>
                    <TextBlock Text="{Binding Year}" FontSize="14"/>
                </StackPanel>
            </StackPanel>
        </Grid>
    </DataTemplate>

</ResourceDictionary>