.NET MAUI › Fundamentals & Architecture

Explain the MAUI app startup and the role of MauiProgram.

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Answer

MAUI uses the .NET Generic Host. MauiProgram.CreateMauiApp() builds a MauiAppBuilder where you register the App class via UseMauiApp<App>(), configure fonts, register services in the DI container, and add handlers or libraries. The builder produces a MauiApp that the platform-specific entry points (MainActivity, AppDelegate) bootstrap.

public static MauiApp CreateMauiApp()
{
    var builder = MauiApp.CreateBuilder();
    builder
        .UseMauiApp<App>()
        .ConfigureFonts(fonts =>
            fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular"));

    builder.Services.AddSingleton<IDataService, DataService>();
    builder.Services.AddTransient<MainPage>();

    return builder.Build();
}

Real-world example A team wires up logging, HTTP clients, and view models in MauiProgram so every page resolves its dependencies from the host container.

Common follow-ups: How is DI configured at startup? | What calls CreateMauiApp?

Dependency Injection Generic Host App Lifecycle