只需基于FrameworkElement.Loaded事件将XAML触发器添加到Window.Triggers下的Window，而无需指定SourceName属性（它将是Window本身）。这就是Blend所做的（afaik）。

XAML：

<Window x:Class="YourNamespace.YourWindow"
    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:YourNamespace"
    mc:Ignorable="d"
    Title="YourWindowTitle" Height="450" Width="800">
    <Window.Resources>
         <Storyboard x:Key="YourStoryboard">
             <!-- Storyboard animations -->
         </Storyboard>
    </Window.Resources>
    <Window.Triggers>
        <!-- This one triggers after Window appears -->
        <EventTrigger RoutedEvent="FrameworkElement.Loaded"> 
            <BeginStoryboard Storyboard="{StaticResource YourStoryboard}"/>
        </EventTrigger>
    </Window.Triggers>
    <Grid>
        <!-- Window content -->
    </Grid>
</Window>