Where to place and configure IoC container in a WPF application?

Question

I am working on a middle sized WPF application (MVVM) that should be extensible and maintainable in the future. Thus I decided to use an IoC container (Unity in this case) to keep things flexible.

However I am not sure where to place and configure Unity in a WPF application.

I guess container should be accessible globally so it should probably go to Application class. But should I make it as static property? Should I configure it in Application_Startup() event handler?

Eg:

/// <summary>
/// Interaction logic for App.xaml
/// </summary>
public partial class App : Application
{
    public static UnityContainer MyUnityContainer;


    private void Application_Startup(object sender, StartupEventArgs e)
    {
        // instantiate and configure Unity
    }
}

This way I will be able to access container from any place in the application via static property:

App.MyUnityContainer

I guess this is one way to do it but I am not sure if there are better practices for this issue, specifically for WPF apps.

Answer 1

Have a look at the Composition Root Pattern. What you want to do is to initialize it in your Startup event handler and forget about its existence for the rest of the application.

You are trying to implement the Service Locator Pattern, which according to many is an inferior solution to this problem.