{"id":3044,"date":"2025-10-25T22:40:49","date_gmt":"2025-10-26T03:40:49","guid":{"rendered":"https:\/\/badecho.com\/?p=3044"},"modified":"2025-10-25T22:40:53","modified_gmt":"2025-10-26T03:40:53","slug":"wpf-with-generic-host","status":"publish","type":"post","link":"https:\/\/badecho.com\/index.php\/2025\/10\/25\/wpf-with-generic-host\/","title":{"rendered":"Running WPF Applications with a Generic Host"},"content":{"rendered":"\n
\"Running<\/figure><\/div>\n\n\n\n

Running a console application using a .NET Generic Host is simple enough; doing the same with a WPF application is another thing altogether.<\/p>\n\n\n\n

A WPF app, being a UI application, has its own internal “hosting” and lifetime mechanisms that are incompatible with the out-of-the-box .NET Generic Host.<\/p>\n\n\n\n

But that doesn’t mean it cannot be done; and, in fact, it can be done relatively cleanly.<\/p>\n\n\n\n

Generic Host: Using vs Running<\/h2>\n\n\n\n

This article demonstrates how to set up a Generic Host to run<\/em> a WPF application. But you might not need to do this.<\/p>\n\n\n\n

You can still use<\/em> a Generic Host and take advantage of many of its features, such as dependency injection, configuration, and logging, all without needing it to run your application.<\/p>\n\n\n\n

If that’s all you require, simply start the host and run your WPF application. Don’t run the host.<\/p>\n\n\n\n

App.xaml.cs – Using the host without running it<\/h6>\n\n\n
\n[STAThread]\npublic static void Main()\n{\n    var builder = Host.CreateApplicationBuilder();\n\n    builder.Services\n           .AddSingleton<MainWindow>()\n           .AddSingleton<MainViewModel>()\n           .AddTransient<FooViewModel>()\n           .AddTransient<BarViewModel>(); \/\/etc.\n\n    IHost host = builder.Build();\n\n    host.Start();\n\n    var app = new App();\n\n    app.InitializeComponent();\n    app.MainWindow = host.Services.GetRequiredService<MainWindow>();\n    app.Run();\n}\n<\/pre>\n\n\n
All you need is something similar to the code above, and you’ll be able to inject view models into views, loggers into view models, etc. You don’t need to do anything else described in this article.<\/p>\n\n\n\n
Conversely, if you want the host to be in charge of the application’s lifetime (perhaps the application is meant to run in the background, whether a UI is currently displayed or not), or to take advantage of lifetime-related features such as IHostedService, then read on to find out how.<\/p>\n\n\n\n
Running the Host: What’s the Problem?<\/h2>\n\n\n\n
The issue with running a host and a WPF application quickly becomes apparent.<\/p>\n\n\n\n
To run the host, we want to call IHost.Run<\/code> instead of IHost.Start<\/code>. Doing so will cause the current thread to block until the host shuts down.<\/p>\n\n\n\n
Consider the following WPF initialization code we were using previously:<\/p>\n\n\n
\n    var app = new App();\n\n    app.InitializeComponent();\n    app.MainWindow = host.Services.GetRequiredService<MainWindow>();\n    app.Run();\n<\/pre>\n\n\n
This code will, of course, never run, because IHost.Run<\/code> blocks. OK, resolving that is simple enough: we’ll move it to some place that will execute after the host has started.<\/p>\n\n\n\n
A perfect place for that is an IHostedService<\/code>. We can start up our App<\/code> instance in the service’s StartAsync<\/code> implementation. Two big problems with that, however:<\/p>\n\n\n\n