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Customizing Initialization

Avalonia provides the AppBuilder API to customize various aspects of the framework.

Because XPF is based upon Avalonia, it can be useful to have access to this API in an XPF application.

Step 1: Disable Automatic XPF Initialization​

In your project file set the DisableAutomaticXpfInit property to true:

<PropertyGroup>
  <DisableAutomaticXpfInit>true</DisableAutomaticXpfInit>
</PropertyGroup>

Step 2: Add a Main Entry-Point​

Add a Program.cs file containing a Main entry-point:

using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.ApplicationLifetimes;
using AvaloniaUI.Xpf;

namespace MyXpfApp;

internal class Program
{
    public static void Main(string[] args)
    {
        AppBuilder.Configure<AvaloniaUI.Xpf.Helpers.DefaultXpfAvaloniaApplication>()
            .UsePlatformDetect()
            .WithAvaloniaXpf()
            .SetupWithLifetime(new ClassicDesktopStyleApplicationLifetime
            { 
                ShutdownMode = ShutdownMode.OnExplicitShutdown 
            });

        App.Main();
    }
}
tip

Change the namespace in the above example to match your application namespace.

In the above example App is your XPF Application class defined in App.xaml.cs.

Step 3: Set the StartupObject​

Configure your project to use the new Main method by adding the following to your .csproj:

 <PropertyGroup>
     <StartupObject>MyXpfApp.Program</StartupObject>
 </PropertyGroup>
tip

Change the namespace in the above example to the namespace defined in Program.cs.

Optional: Define a custom Avalonia Application​

In certain cases you may want to use a custom Avalonia Application class; some use-cases for this scenario are:

  • Providing application-wide Avalonia styles and resources
  • Providing an application NativeMenu

In order to do this, first add .cs and .axaml files for your application class:

MyAvaloniaApp.axaml.cs
using Avalonia;
using Avalonia.Markup.Xaml;
using Avalonia.Styling;

namespace MyXpfApp;

public class MyAvaloniaApp : Application
{
    public MyAvaloniaApp()
    {
        RequestedThemeVariant = ThemeVariant.Light;
        AvaloniaXamlLoader.Load(this);
    }
}
MyAvaloniaApp.axaml
<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="MyXpfApp.MyAvaloniaApp">
  <Application.Styles>
    <SimpleTheme/>
  </Application.Styles>
</Application>

And then reference this custom Application in the AppBuilder configuration added in step 2:

AppBuilder.Configure<MyAvaloniaApp>()
    .UsePlatformDetect()
    .WithAvaloniaXpf()
    .SetupWithLifetime(new ClassicDesktopStyleApplicationLifetime
    { 
        ShutdownMode = ShutdownMode.OnExplicitShutdown 
    });