README.md

Microsoft.Extensions.Hosting.Wpf

Unofficial implementation of Microsoft.Extensions.Hosting for WPF. It is inspired by Dapplo and this extensions is focused only on WPF and doesn't have Plugins, SingleInstance etc features like Dapplo. It's main feature is to provide the ability to bind DataContext with ViewModels directly in XAML where the ViewModel gets resolved by DI. This library also has few extensions packages to add features like tray icon, thread swithcing between main thread and threadpool thread, 3rd party DI support.

Changelog

Samples

1. HostingSimple: This project serves as a minimalistic, beginner-friendly introduction. It offers a basic starting point for understanding the Microsoft.Extensions.Hosting.Wpf framework.
2. HostingReactiveUI: In this more advanced example, NLog is utilized for logging, and ReactiveUI is employed as the model-view-viewmodel framework. Additionally, the example showcases the integration of the TrayIcon feature.
3. HostingReactiveUISimpleInjector: Similar to HostingReactiveUI, this project not only employs ReactiveUI but also incorporates SimpleInjector. This library doesn't limits your to stick only with Microsoft.DependencyInjection. This example further provides insights into additional abstractions and internal utilities for managing different DI frameworks.
4. HostingReactiveUISimpleInjectorAmbientScope: Building upon the concepts of HostingReactiveUISimpleInjector, this project delves into the application of the AsyncScopedLifestyle with SimpleInjector. This advanced example illustrates the support for ambient-scoping, as described in The Ambient Composition Model. Moreover, it demonstrates the integration of Microsoft.Extensions.Hosting.Wpf.Threading.
5. HostingReactiveUISimpleInjectorFlowingScope: Building upon the concepts of HostingReactiveUISimpleInjector, this project delves into the application of the ScopedLifestyle.Flowing with SimpleInjector (similar mechanisms that is used by Microsoft DI). This advanced example illustrates the support for closure-scoping, as described in The Closure Composition Model. This sample doesn't use the ViewModelLocatorHost, presenting an alternative approach for leveraging IViewModelLocator to inject view models for views. It also showcases the integration of Microsoft.Extensions.Hosting.Wpf.Threading.

Getting Started

This steps including the Locator feature for Views. If you don't want it then just skip to 6 and 7 step.

In fact, it has alternative method to inject ViewModels to View. Usually used when you need to use closure-scoping with DI. Please, refer to HostingReactiveUISimpleInjectorFlowingScope sample for such scenario.

1. First step, make IViewModelLocator that will contain your ViewModels. Example:

public interface IViewModelLocator
{
    MainViewModel Main { get; }

    ChildViewModel Child { get; }
}

2. Make implementation for IViewModelLocator. This example is using IServiceProvider

public class ViewModelLocator : IViewModelLocator
{
    public IServiceProvider Container { get; }

    public MainViewModel Main => Container.GetRequiredService<MainViewModel>();

    public ChildViewModel Child => Container.GetRequiredService<ChildViewModel>();

    public ViewModelLocator(IServiceProvider container)
    {
        Container = container;
    }
}

3. Add ViewModelLocatorHost that inherits AbstractViewModelLocatorHost<IViewModelLocator>

public class ViewModelLocatorHost : AbstractViewModelLocatorHost<IViewModelLocator>
{
}

4. In your App.xaml add Locator resource

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <!--Resources that you need, for example MahApps-->
        </ResourceDictionary.MergedDictionaries>
        <locator:ViewModelLocatorHost x:Key="Locator"/>
    </ResourceDictionary>
</Application.Resources>

5. Add in App.xaml.cs two interfaces IViewModelLocatorInitialization<ViewModelLocator> and IApplicationInitializeComponent

public partial class App : Application, IViewModelLocatorInitialization<IViewModelLocator>, IApplicationInitializeComponent
{
    public void Initialize()
    {
        //Here we can initialize important things. This method always runs on UI thread. 
        //In this example it's empty as we do not have anything to initialize like ReactiveUI
    }
	
    public void InitializeLocator(IViewModelLocator viewModelLocator)
    {
        //Runs after Initialize method.
        //We need to set it so that our <locator:ViewModelLocatorHost x:Key="Locator"/> could resolve ViewModels for DataContext
        //You can also use it as service locator pattern, but I personally recommend you to use it only inside View xaml to bind the DataContext
        var viewModelLocatorHost = ViewModelLocatorHost.GetInstance(this);
        viewModelLocatorHost.SetViewModelLocator(viewModelLocator);
    }
}

NB! ViewModelLocatorHost.GetInstance(this) will automatically find the locator even if you rename it(x:Key) in App.xaml, but for better perfomance, startup time, memory usage(it will iterate through Application Dictionary) my personal recommendation is to use ViewModelLocatorHost.GetInstance(this, "Locator") instead.

6. Add Program.cs. Basic example

public class Program
{
	/// <summary>
	/// The main entry point for the application.
	/// </summary>
	public static void Main(string[] args)
	{
		using IHost host = CreateHostBuilder(args)
			.Build()
			.UseWpfViewModelLocator<App, IViewModelLocator>(provider => new ViewModelLocator(provider));
		host.Run();
	}

	private static IHostBuilder CreateHostBuilder(string[] args)
	{
		return Host.CreateDefaultBuilder(args)
			.ConfigureServices(ConfigureServices);
	}

	private static void ConfigureServices(HostBuilderContext hostContext, IServiceCollection services)
	{
		services.AddLogging();
		services.AddWpf<App>();

		//Add our view models
		services.AddTransient<MainViewModel>();
		services.AddTransient<ChildViewModel>();
	}
}

7. We need to add StartupObject in our .csproj

<StartupObject>[Namespace].Program</StartupObject>

8. Now in your View you can bind the DataContext like this

DataContext="{Binding ViewModelLocator.Main, Mode=OneTime, Source={StaticResource Locator}}"

WPF Lifetime

If you want you can use UseWpfLifetime but it's pretty much experimental, the current solution is well adopted to use the default lifetime and was battle tested without UseWpfLifetime.

Usage

private static IHostBuilder CreateHostBuilder(string[] args)
{
	return Host.CreateDefaultBuilder(args)
		.UseWpfLifetime() //<-- new line
		.ConfigureServices(ConfigureServices);
}

Other features

1. Microsoft.Extensions.Hosting.Wpf.Threading
2. Microsoft.Extensions.Hosting.Wpf.Bootstrap
3. Microsoft.Extensions.Hosting.Wpf.TrayIcon