Dependency injection in WPF project with .net core

DI WPF-C#.md

Dependency injection in WPF project with .net core

Delete StartupUri="MainWindow.xaml" from App.xaml

Install packages :

Microsoft.Extensions.Configuration.Json
Microsoft.Extensions.DependencyInjection
Microsoft.Extensions.Options.ConfigurationExtensions

Add the file appsettings.json in the root of the project to use it for configuration.

Override OnStartup method in App.Xaml.Cs class :

public IServiceProvider ServiceProvider { get; private set; }

public IConfiguration Configuration { get; private set; }

protected override void OnStartup(StartupEventArgs e)
{
    var builder = new ConfigurationBuilder()
     .SetBasePath(Directory.GetCurrentDirectory())
     .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true);

    Configuration = builder.Build();

    var serviceCollection = new ServiceCollection();
    ConfigureServices(serviceCollection);

    ServiceProvider = serviceCollection.BuildServiceProvider();

    var mainWindow = ServiceProvider.GetRequiredService<MainWindow>();
    mainWindow.Show();
}

private void ConfigureServices(IServiceCollection services)
{
    services.Configure<AppSettings>(Configuration.GetSection(nameof(AppSettings)));

    services.AddTransient(typeof(MainWindow));
}

Hi again (sorry for the long delay)

The problem with constructor injection in WPF is that usercontrol hierachy and how one would normally write XAML, wont use the serviceprovider to fetch usercontrols.

eg

<VehicleManager> 
    <VehicleList>
       <ItemsControl>
             <Vehicle>

Vehicles are generated on the fly by the XAML binding and wont be requested from the ServiceProvider.
Usually controls are spawned from the UI rather than from the codebehind...

So i dont know how useful DI is for WPF...

I am struggling to pass the viewmodel to the view as a parameter constructor, while still being able to design my UI in xaml.
I randomly came across this discussion, is there any possibility that you found an elegant solution?

I am struggling to pass the viewmodel to the view as a parameter constructor, while still being able to design my UI in xaml. I randomly came across this discussion, is there any possibility that you found an elegant solution?

If your viewmodel only exists once: use Singleton and simply reference it in your usercontrol

if your viewmodel exists pr usercontrol / window, instantiate a new one and pass it to the constructor or instantiate it in the constructor .... or do everything like MVC and let the codebehind be the Viewmodel ... usually the easiest option.

ViewModels only make sense if they aggregate several UserControls

btw.. I've given up on using DI for WPF .. it makes no sense