docs-desktop/dotnet-desktop-guide/net/wpf/events/snippets/marking-routed-events-as-handled-and-class-handling/csharp/App.xaml.cs

using System.Windows;

namespace CodeSampleCsharp
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
    }
}