Using OmniXAML for WPF

1. Create a new project of type "WPF Application" and be sure that you select at least .NET Framework 4.5.2
2. Install the NuGet package: OmniXaml.Wpf.
3. Go to the Properties page of MainWindow.xaml and set the property Copy to Output Directory to either Copy always or Copy if newer.
4. Delete MainWindow.xaml.cs (the code-behind file). It won't compile if you don't delete it.
5. Open MainWindow.xaml and replace its content with this:

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        Title="MainWindow" Height="350" Width="525">
        <TextBlock Text="Hello World!" />
</Window>

5. Open App.xaml and remove the part that says StartupUri="MainWindow.xaml"
6. Open App.Xaml.cs and add this method inside the App class:

    protected override void OnStartup(StartupEventArgs e)
    {
        var xamlLoader = new WpfXamlLoader();

        Window mainWindow;
        using (var stream = new FileStream("MainWindow.xaml", FileMode.Open))
        {
            mainWindow = (Window) xamlLoader.Load(stream);
        }

        mainWindow.Show();
    }

Don't forget to add the using OmniXaml.Wpf; part along with the other using statements ;)

7. Run it!