.NET MAUI Documentation

Introduction to .NET MAUI

.NET Multi-platform App UI (.NET MAUI) is an open-source, cross-platform framework for creating native mobile and desktop applications with C# and XAML from a single shared codebase. It's the evolution of Xamarin.Forms and provides a modern, unified way to build applications that run on Android, iOS, macOS, and Windows.

With .NET MAUI, you can leverage your existing C# and .NET skills to build visually stunning, high-performance applications for a wide range of platforms. It simplifies development by abstracting away platform-specific UI paradigms and providing a consistent API surface.

Key benefits of .NET MAUI include:

• Single Codebase: Write your UI and business logic once and deploy it across multiple platforms.
• Native Performance: Apps compiled with .NET MAUI deliver native performance and a native look and feel.
• Modern Tooling: Integrates seamlessly with Visual Studio and Visual Studio Code.
• Rich Platform Access: Access to native device APIs and features.
• Extensibility: Easily extend the framework with custom renderers or handlers.

Getting Started

To get started with .NET MAUI, you'll need to install the .NET SDK and the necessary workloads.

Ensure you have the latest .NET SDK installed. Then, open your terminal or command prompt and run the following commands:

dotnet workload install maui
dotnet workload install maui-android
dotnet workload install maui-ios
dotnet workload install maui-maccatalyst
dotnet workload install maui-windows

Once the workloads are installed, you can create a new .NET MAUI project using the .NET CLI:

dotnet new maui -n MyMauiApp
cd MyMauiApp
dotnet build
dotnet run

For a more detailed setup guide, refer to the official .NET MAUI documentation on setup.

Core Concepts

.NET MAUI revolves around several key concepts:

Views and Layouts

Views are the building blocks of your UI, such as buttons, labels, and images. Layouts are used to arrange these views on the screen. .NET MAUI provides a rich set of pre-built views and layouts that can be combined to create complex UIs.

XAML

XAML (Extensible Application Markup Language) is an XML-based language that allows you to define your application's user interface declaratively. It separates the UI from the application logic, making your code cleaner and more maintainable.

Data Binding

Data binding is a powerful mechanism that allows you to connect UI elements to data sources. When the data changes, the UI automatically updates, and vice-versa. This significantly reduces boilerplate code and improves the responsiveness of your application.

MVVM Pattern

The Model-View-ViewModel (MVVM) architectural pattern is highly recommended for .NET MAUI development. It promotes separation of concerns, making your code easier to test, maintain, and scale.

UI Design with .NET MAUI

.NET MAUI offers flexible ways to design your user interface:

XAML-Based UI

The most common approach is to use XAML for defining your UI. This provides a clear and declarative way to lay out your controls and bind them to data.

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyMauiApp.MainPage"
             Title="Home">
    <VerticalStackLayout
        Spacing="25"
        Padding="30,0"
        VerticalOptions="Center">

        <Image
            Source="dotnet_logo.png"
            SemanticProperties.Description="dotnet MAUI logo"
            HeightRequest="200"
            HorizontalOptions="Center" />

        <Label
            Text="Hello, .NET MAUI!"
            SemanticProperties.HeadingLevel="Level1"
            FontSize="32"
            HorizontalOptions="Center" />

        <Button
            x:Name="CounterBtn"
            Text="Click me"
            SemanticProperties.Hint="Counts the number of times you have clicked"
            Clicked="OnCounterClicked"
            HorizontalOptions="Center" />
    </VerticalStackLayout>
</ContentPage>

C# UI

You can also define your UI entirely in C# code, which can be useful for dynamic UI generation or specific scenarios.

Styling and Theming

.NET MAUI supports advanced styling capabilities, including resource dictionaries, styles, and themes, allowing you to create consistent and branded user experiences across your application.

Data Binding

Data binding is a cornerstone of efficient .NET MAUI development. It simplifies the process of synchronizing data between your UI elements and your application's data model.

Binding Context

The BindingContext property is central to data binding. When set on a control or a page, it establishes the data source for bindings within that scope.

Binding Modes

You can specify the direction of data flow with different binding modes:

• OneWay: Changes in the source update the target.
• TwoWay: Changes in the source update the target, and changes in the target update the source.
• OneTime: The source updates the target once.
• OneWayToSource: Changes in the target update the source.

Example Binding

Consider a Slider and a Label where the label displays the slider's value:

<!-- XAML -->
<Slider Value="{Binding SliderValue, Mode=TwoWay}" />
<Label Text="{Binding SliderValue, StringFormat='Value: {0:F2}'}" />

<!-- C# ViewModel -->
public partial class MyViewModel : ObservableObject
{
    [ObservableProperty]
    double sliderValue;
}

In this example, the SliderValue property in the ViewModel is bound to both the Slider's Value and the Label's Text.

Accessing Platform APIs

.NET MAUI allows you to access native device capabilities and APIs. While it provides a cross-platform abstraction for common features, you can also tap into platform-specific functionality when needed.

Platform-Specific Code

You can use conditional compilation or platform-specific projects to write code that only runs on certain platforms.

#if ANDROID
    // Android-specific code
    public void DoSomethingAndroid() { }
#elif IOS
    // iOS-specific code
    public void DoSomethingIOS() { }
#endif

Device Information

The DeviceInfo static class provides information about the device, such as its model, manufacturer, and operating system version.

Sensors and Services

.NET MAUI offers abstractions for accessing device sensors like the accelerometer and compass, as well as services like geolocation and preferences.

Deployment

Deploying your .NET MAUI application involves building and packaging it for each target platform.

Packaging

For each platform, you'll generate a deployment package:

• Android: APK or App Bundle.
• iOS: IPA file, often deployed via App Store Connect or TestFlight.
• macOS: .app bundle, deployable via the Mac App Store.
• Windows: MSIX package, deployable via the Microsoft Store or sideloading.

CI/CD Integration

.NET MAUI applications can be integrated into continuous integration and continuous delivery (CI/CD) pipelines using tools like Azure DevOps, GitHub Actions, or Jenkins to automate the build, test, and deployment process.