Configure CI pipeline with .NET MAUI Release candidate (for NuGets)

In order to do automated builds in Azure DevOps with the .NET MAUI Release Candidate release, we need a few extra steps in the pipeline configuration. I used these steps to ensure that the NuGet packages I develop are automatically compiled and uploaded to NuGet.org. In this article I won’t go into detail about how to create a CI pipeline, I just want to show you the difference from a normal CI pipeline. I haven’t tried building and deploying applications in the cloud at the moment, but it can probably be done. Also, I don’t go into how to make the package automatically go to NuGet.org, for that I recommend an earlier article (and also how to create a CI/CD pipeline): https://www.banditoth.net/2021/11/09/azure-devops-setup-private-nuget-feed-with-ci/

Since a final version of .NET MAUI has not been released as of today, in order to build our applications in the cloud, we need to install the MAUI Workload on the Agent.
If we do not do this, we may encounter the following error:

Error NETSDK1147: To build this project, the following workloads must be installed: maui-windows

Adjust your pipeline

In order to install the workload on our build agent, create a new task at the very beginning in the pipeline file, which is executes a command in the command line:

This will result the following task in the yaml file:

- task: CmdLine@2
  inputs:
    script: 'dotnet workload install maui'

The installation of the workload will take about 5 minutes.

From now on, you will be able to use .NET Maui references on the pipelines too. This will let you build your packages in the cloud.
Once MAUI will be officially available, probably you don’t need these steps.

.NET MAUI RC1 is available with VS for Mac support

Good news for .NET MAUI fans. We’ll soon have a stable version from the wonderful developers at Microsoft, but in the meantime, here we have the first RC version of .NET MAUI.
There’s a lot of new features in this version, including integration with the Essentials package, much more customizable styles, etc.
But today I want to talk about the most important thing for me, which is the support for Visual Studio for Mac. Well, it’s not so official yet, and it’s not so usable, but we can see progress. VS for Mac 2022 is no longer a stranger to MAUI projects. Unfortunately, I couldn’t get the debugging to work, but you can now start the project on almost any platform.

Let’s use MAUI in Visual Studio 2022 for Mac

First and most importantly, and I experienced it first hand.
If the IDE you want to use throws the following errors:

/usr/local/share/dotnet/sdk/6.0.202/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.ImportWorkloads.targets(5,5): Error NETSDK1147: To build this project, the following workloads must be installed: maui-maccatalyst
To install these workloads, run the following command: dotnet workload install maui-maccatalyst (NETSDK1147) (ResxEditorMaui)

/usr/local/share/dotnet/sdk/6.0.202/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.ImportWorkloads.targets(5,5): Error NETSDK1147: To build this project, the following workloads must be installed: maui-ios
To install these workloads, run the following command: dotnet workload install maui-ios (NETSDK1147) (ResxEditorMaui)

/usr/local/share/dotnet/sdk/6.0.202/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.ImportWorkloads.targets(5,5): Error NETSDK1147: To build this project, the following workloads must be installed: maui-android
To install these workloads, run the following command: dotnet workload install maui-android (NETSDK1147) (ResxEditorMaui)

And you can’t install the recommended packages because the following error is displayed:

Workload ID android-aot is not recognized.

Then be sure to install .NET version 6.0.3XX. You can do this from this url and select the appropriate processor architecture. https://github.com/dotnet/installer

To check which version is installed, you can check in the terminal with the following paranncs:

dotnet --info

If you have installed the required version of .NET 6.0, issue the following command:

sudo dotnet workload install maui

You can then use MAUI in Visual Studio for Mac.

The easiest and best MVVM toolkit also for .NET MAUI.

Guys, this is unbelievable. Microsoft Community toolkit has added a tool that means you never have to worry about which MVVM framework you’re voting for. None can be as good as this one. It can be used not only for .NET MAUI, but also for other technologies (e.g. WPF). But before I sing your praises, let’s look at what this package has to offer us:

Introducing CommunityToolkit.Mvvm

First of all, you don’t need to implement INotifyPropertyChanged in ViewModels. And by that I mean not even its parent classes. Since this component is a code generator, it’s enough to make your classes partial, and the INotifyPropertyChanged implementation is done by it, instead of you. This means that your class will be supplemented with the best implementation so that you can easily use common methods like SetProperty in the setter branch of your properties. Okay, okay, but almost any MVVM framework could do this, and you didn’t even need to use a code generator, just simply derive from a parent class. I’ll do you one better: what if you didn’t have to write the setter and getter branches of the properties at all? What if the toolkit made them itself? If you could implement a property declaration from two lines of code?
Well, that’s what makes this toolkit good: It does all that for you.

And if that’s not enough, you don’t even have to bother creating Commands. The toolkit automatically creates a command for you from your methods.
But let’s see how you can use it.

Use CommunityToolkit.MVVM in .NET MAUI

Let’s see what my ViewModel looked like before I used this toolkit:

namespace Carloo.ViewModels.SignInPage
{
    public partial class SignInPageViewModel : BaseViewModel
    {
        private Command signInCommand;
        public Command SignInCommand
        {
            get { return signInCommand ?? (signInCommand = new Command(() => _ = SignIn(), () => true)); }
        }

        private string userName;
        public string UserName
        {
            get { return userName; }
            set { SetProperty(ref userName, value, nameof(UserName)); }
        }

        private string password;
        public string Password
        {
            get { return password; }
            set { SetProperty(ref password, value, nameof(Password)); }
        }

        public SignInPageViewModel()
        {

        }

        private void SignIn()
        {
            try
            {
                ...
            }
            catch (Exception ex)
            {
                // todo error
            }
        }
    }
}

And now let’s see what this Toolkit can do with source code to make life easier:

namespace Carloo.ViewModels.SignInPage
{
    [INotifyPropertyChanged]
    public partial class SignInPageViewModel
    {
        [ObservableProperty]
        private string userName;

        [ObservableProperty]
        private string password;

        public SignInPageViewModel()
        {

        }

        [ICommand]
        private void SignIn()
        {
            try
            {
                ...
            }
            catch (Exception ex)
            {
                // todo error
            }
        }
    }
}

In other ways, however, Resharper also had the tools to provide similar simplicity for implementing MVVM. But if I remember correctly, it didn’t have all that. Like, say, that you could release PropertyChanged on a completely unrelated property, even with an attribute declaration, without writing code.

        [ObservableProperty]
        [AlsoNotifyFor(nameof(CanSignIn))]
        private string _userName;

        [ObservableProperty]
        [AlsoNotifyFor(nameof(CanSignIn))]
        private string _password;


        public bool CanSignIn { get => !string.IsNullOrWhiteSpace(UserName) && !string.IsNullOrWhiteSpace(Password); }

Learn more

I am very excited about using this tool in production environments. If you want to learn more about it, please visit the following pages:
https://devblogs.microsoft.com/ifdef-windows/announcing-net-community-toolkit-v8-0-0-preview-1/
https://docs.microsoft.com/en-gb/windows/communitytoolkit/mvvm/introduction

.NET MAUI: App.xaml, MainPage.xaml is missing from the project

.NET MAUI is still in beta so there are no final project templates to create a new MAUI application. The current project template omits the App.xaml, and MainPage.xaml files from the project (at least on mac), so we have to add them ourselves.

Enable on Visual Studio, to show all files

Enable showing all files

And select the missing files, then right click on them, and add them to the project.

Include the missing files to the project

Run .NET MAUI apps with Visual Studio for Mac

VS for Mac 17.0 Preview version is not yet supporting MAUI applications. But you can run them on macOS too, but you will need a terminal window for it!

MAUI projects can not be set as a runnable project (yet)
.NET 6 Xamarin and MAUl projects are not supported with this version of Visual Studio. The included target frameworks are not supported: net6.0-android|net6.0-ios|net6.0-maccatalyst

If you are not familiar, how to set up your environment to start developing with .NET newest technology named MAUI, then read this article by me: https://www.banditoth.hu/2021/12/29/setup-net-maui-project-on-macos/

Build and run on macOS

Open up a terminal, and navigate next to your .sln file. Give out the following command:

dotnet build YourSolutionName -t:Run -f net6.0-maccatalyst

This will run your application on macOS. If you wish, you can change the last parameter to net6.0-android or net6.0-ios too.