.NET MAUI Blazor Hybrid Development

Expert guidance for building cross-platform apps with .NET MAUI and Blazor.

Implementation Workflow

1. Analysis Phase (Required)

Before implementation, determine:

• App type: Pure MAUI Blazor or MAUI + Blazor Web App (shared UI)
• Platform targets: Android, iOS, Windows, macOS
• Native features needed: Sensors, camera, file system, notifications
• State management: Component state, MVVM, or hybrid approach
• Navigation pattern: Blazor-only, Shell, or mixed navigation

2. Architecture Decision

| Scenario | Recommended Approach | |----------|---------------------| | Mobile-first with some web | maui-blazor template | | Shared UI across mobile + web | maui-blazor-web template with RCL | | Complex native integration | MVVM with platform services | | Simple data-driven UI | Component state with DI services |

3. Project Setup

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

    builder.Services.AddMauiBlazorWebView();
#if DEBUG
    builder.Services.AddBlazorWebViewDeveloperTools();
#endif

    // Register services
    builder.Services.AddSingleton<IDeviceService, DeviceService>();
    builder.Services.AddScoped<IDataService, DataService>();

    return builder.Build();
}

4. BlazorWebView Configuration

<!-- MainPage.xaml -->
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:b="clr-namespace:Microsoft.AspNetCore.Components.WebView.Maui;assembly=Microsoft.AspNetCore.Components.WebView.Maui">
    <b:BlazorWebView HostPage="wwwroot/index.html">
        <b:BlazorWebView.RootComponents>
            <b:RootComponent Selector="#app" ComponentType="{x:Type local:Main}" />
        </b:BlazorWebView.RootComponents>
    </b:BlazorWebView>
</ContentPage>

Core Patterns

Dependency Injection

| Lifetime | Use Case | |----------|----------| | AddSingleton<T> | App-wide state, device services, settings | | AddScoped<T> | Per-BlazorWebView instance state | | AddTransient<T> | Stateless utilities, factories |

// Interface for platform-specific implementation
public interface IDeviceService
{
    string GetDeviceModel();
    Task<bool> HasPermissionAsync(string permission);
}

// Platform implementation registered in MauiProgram.cs
builder.Services.AddSingleton<IDeviceService, DeviceService>();

Component Lifecycle

@code {
    [Parameter] public string Id { get; set; } = "";

    // Called once when component initializes
    protected override async Task OnInitializedAsync()
    {
        await LoadDataAsync();
    }

    // Called when parameters change (including first render)
    protected override void OnParametersSet()
    {
        // React to parameter changes
    }

    // Called after each render
    protected override void OnAfterRender(bool firstRender)
    {
        if (firstRender)
        {
            // JS interop safe here
        }
    }
}

Platform Feature Access

// Check platform and access native features
@inject IDeviceService DeviceService

@if (DeviceInfo.Current.Platform == DevicePlatform.Android)
{
    <AndroidSpecificComponent />
}

@code {
    private async Task AccessCameraAsync()
    {
        var status = await Permissions.CheckStatusAsync<Permissions.Camera>();
        if (status != PermissionStatus.Granted)
        {
            status = await Permissions.RequestAsync<Permissions.Camera>();
        }

        if (status == PermissionStatus.Granted)
        {
            // Use camera
        }
    }
}

State Updates from External Events

@implements IDisposable
@inject IDataService DataService

<p>@message</p>

@code {
    private string message = "";

    protected override void OnInitialized()
    {
        DataService.OnDataChanged += HandleDataChanged;
    }

    private async void HandleDataChanged(object? sender, EventArgs e)
    {
        message = "Data updated!";
        await InvokeAsync(StateHasChanged); // Required for external events
    }

    public void Dispose()
    {
        DataService.OnDataChanged -= HandleDataChanged;
    }
}

Reference Documentation

For detailed patterns and examples, see:

• Project Structure: Solution templates, RCL setup, multi-targeting
• Blazor Components: Lifecycle, RenderFragment, EventCallback, data binding
• Platform Integration: Device APIs, permissions, platform-specific code
• Navigation & Routing: Blazor routing, Shell, deep linking
• State Management: MVVM, DI patterns, CommunityToolkit.Mvvm

Quick Reference

Common Service Registration

// Services
builder.Services.AddSingleton<ISettingsService, SettingsService>();
builder.Services.AddSingleton<IConnectivity>(Connectivity.Current);
builder.Services.AddSingleton<IGeolocation>(Geolocation.Default);

// ViewModels (if using MVVM)
builder.Services.AddTransient<MainViewModel>();
builder.Services.AddTransient<SettingsViewModel>();

// Pages with DI
builder.Services.AddTransient<MainPage>();

Platform Checks

// Runtime platform check
if (DeviceInfo.Current.Platform == DevicePlatform.iOS) { }
if (DeviceInfo.Current.Platform == DevicePlatform.Android) { }
if (DeviceInfo.Current.Platform == DevicePlatform.WinUI) { }
if (DeviceInfo.Current.Platform == DevicePlatform.macOS) { }

// Compile-time platform check
#if ANDROID
    // Android-specific code
#elif IOS
    // iOS-specific code
#elif WINDOWS
    // Windows-specific code
#endif

Navigation Patterns

// Blazor navigation (within BlazorWebView)
@inject NavigationManager Navigation
Navigation.NavigateTo("/details/123");

// MAUI navigation (to other pages)
await Navigation.PushAsync(new SettingsPage());
await Shell.Current.GoToAsync("//settings");