Slides of my presentation about Migrating your Xamarin.Forms mobile apps to .NET MAUI at .NET Conf Bhubaneswar community event

2. Migrating your
Xamarin.Forms app
to .NET MAUI
Luis Beltrán

3. • Researcher at Tomás Bata
University in Zlín, Czech Republic
• Lecturer at Tecnológico Nacional
de México en Celaya, Mexico
• Microsoft MVP (AI + Developer
Technologies)
@darkicebeam
luis@luisbeltran.mx

4. Xamarin
An open source Microsoft platform to build iOS, Android, macOS,
Windows, watchOS, & tvOS modern and high-performant
apps with .NET.

5. Xamarin.Forms
Xamarin.Forms
Xamarin Traditional
iOS C# UI Windows C# UI
Android C# UI
Shared C# Logic Shared C# Logic
Xamarin.Forms
Shared codebase • 100% access to Native APIs • High performance

6. .NET MAUI
• Native UI, multiplatform
• Single Project system
• One shared codebase
• Deploy on multiple devices: mobile & desktop
• .NET 6
.NET 6
.NET Multi-platform App UI
WinUI
Mac
Catalyst
Android
iOS
iOS
macOS
github.com/dotnet/maui
https://docs.microsoft.com/en-us/dotnet/maui/

7. Designing UI in .NET MAUI
XAML, C#, y MVVM

8. Customize .NET controles with handlers

9. Customizing controls
#if ANDROID
Handlers.EntryHandler
.EntryMapper[nameof(IEntry.BackgroundColor)] = (h, v) =>
{
(h.NativeView as global::Android.Views.Entry).UnderlineVisible =
false
};
#endif
#ifdef if platform specific
Access the handler from anywhere
Dictionary of all props

10. Single Project
• Simplified app development.
• One project
• Deploy to multiple devices and
platforms
• Single location for resources:
(fonts, images, App Icons,
splash screens, assets)
• Platform-code organization

11. Fundamentals
• App Class  App entry point
• MauiProgram Class
• Font registration
• Handlers registration
• Renderers registration

12. Maui.Essentials
Use Maui.Essentials to access device
services in all .NET MAUI targets.
“Evolution” of Xamarin.Essentials

13. Migrating from Xamarin.Forms –
Manual steps
• Convert the projects from .NET Framework to .NET SDK Style
• Update code namespaces
• Update any incompatible NuGet packages
• Address any breaking API changes
https://github.com/dotnet/maui/wiki/Migrating-from-Xamarin.Forms-(Preview)

14. • Copy the code files (except App.xaml) into your project.
• Find and Replace:
• using Xamarin.Forms 
using Microsoft.Maui & using Microsoft.Maui.Controls
• using Xamarin.Forms.Xaml 
using Microsoft.Maui.Controls.Xaml
• xmlns="http://xamarin.com/schemas/2014/forms" 
xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
• Pass false to UseFormsCompatibility.
• Emulator, simulator, or device should be up and running.

15. Demo – Migrating a
Xamarin.Forms app to .NET
MAUI

16. Demo
Back2LearnApp Xamarin.Forms
https://github.com/icebeam7/Back2LearnApp
Back2LearnApp .NET MAUI project
https://github.com/icebeam7/Back2LearnMauiApp

18. .NET Upgrade Assistant is here to help!
• Install the .NET Upgrade Assistant dotnet tool:
dotnet tool install --global upgrade-assistant -
-version 0.3.242703
• Start the upgrade process and follow the instructions:
upgrade-assistant upgrade <Path to csproj/sln>
• Beware!
• Preview version
• Use source control
https://github.com/dotnet/maui/wiki/Migrating-from-Xamarin.Forms-(Preview)
https://github.com/dotnet/upgrade-assistant/

19. Limitations
• Your app bust be on Xamarin.Forms 4.8 or higher
• Only works with Xamarin.Forms .slns
• Will not work with binding or library projects
• You’ll still have to do some manual changes too

20. Demo – .NET Upgrade
Assistant

21. Prerequisites
For a better chance of success when migrating to .NET 6 it is
recommended to:
• Upgrade any PCL project to .NET Standard
• Upgrade Xamarin.Forms projects to version 5.0
• Update packages.config to PackageReference

22. Know your project dependencies
How do I know if a NuGet dependency needs to be updated or
replaced?
Case 1
.NET Standard Nugets which do not reference any Xamarin.Forms
type will likely work as they are.
Case 2
NuGets that reference Xamarin.Forms types must be updated to
Microsoft.Maui.Controls types and republished with .NET 6 Target
Frameworkd

23. Should the project be migrated to
"Single Project"?
• No, your existing projects will continue to work without
Single Project.
• You can migrate existing projects to the .NET 6 common
project system.
• Documentation will be provided if you want to adopt Single
Project manually.

24. Do I need to rewrite my custom
renderers?
No. Custom Renderers will continue working as they are.

25. Xamarin.Forms  Microsoft.Maui
.NET MAUI can run Effects and Custom Renderers
Update the namespaces in your platform code to Microsoft.Maui
1. Register your Effect in Startup.cs:
2. Register your Renderer in Startup.cs:
No change required in XAML
appBuilder.ConfigureEffects(builder => {
builder.Add<FocusRoutingEffect, FocusPlatformEffect>();
});
appBuilder.ConfigureMauiHandlers(builder => {
#if __ANDROID__
handlers.AddCompatibilityRenderer(typeof(CustomEntry),
typeof(Droid.Renderers.CustomEntryRenderer));
#endif
});

26. Xamarin.Forms  Microsoft.Maui
(Optional)
• Migrate Effects and Renderers to the Handlers new
architecture
• Migrate Multiple Project solutions to Single project
Examples and resources: https://github.com/jsuarezruiz/xamarin-forms-to-net-maui

27. Will third-party UI libraries still work?
Yes! At a minimum, they will need to recompile by adding a
target for .NET 6.

28. What "flavor" of XAML will .NET MAUI use?
• The same XAML you use in Xamarin.Forms today.
• Previews will provide insight on any name changes.

29. Xamarin.Forms  Microsoft.Maui
.NET MAUI uses the same
XAML and controls as
Xamarin.Forms

30. Q & A

31. Thank you for your attention!
Luis Beltrán
Tomás Bata University in Zlín
Tecnológico Nacional de México en Celaya
about.me/luis-beltran/