Avalonia/samples/ControlCatalog/MainWindow.xaml

<Window xmlns="https://github.com/avaloniaui" MinWidth="500" MinHeight="300"
        xmlns:pages="clr-namespace:ControlCatalog.Pages"
        Title="Avalonia Control Gallery"
        Icon="/Assets/test_icon.ico"
        xmlns:local="clr-namespace:ControlCatalog"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="clr-namespace:ControlCatalog.ViewModels"
        xmlns:v="clr-namespace:ControlCatalog.Views"
        x:Class="ControlCatalog.MainWindow">
    <Window.DataTemplates>
        <DataTemplate DataType="vm:NotificationViewModel">
            <v:CustomNotificationView />
        </DataTemplate>
    </Window.DataTemplates>
    <Panel>
        <local:MainView/>
    </Panel>
</Window>