ASP.NET Core DependencyResolver

Question

In ASP.NET MVC 5 is possible to obtain some dependency through DependencyResolver.Current.GetService(). Is there something similar in ASP.NET Core?

Answer 1

If you really need it, you can write own one. First - create AppDependencyResolver class.

public class AppDependencyResolver
{
    private static AppDependencyResolver _resolver;

    public static AppDependencyResolver Current
    {
        get
        {
            if (_resolver == null)
                throw new Exception("AppDependencyResolver not initialized. You should initialize it in Startup class");
            return _resolver;
        }
    }

    public static void Init(IServiceProvider services)
    {
        _resolver = new AppDependencyResolver(services);
    }

    private readonly IServiceProvider _serviceProvider;

    public object GetService(Type serviceType)
    {
        return _serviceProvider.GetService(serviceType);
    }

    public T GetService()
    {
        return _serviceProvider.GetService();
    }

    private AppDependencyResolver(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }
} 

Please note that _serviceProvider.GetService(); only available if you add using Microsoft.Extensions.DependencyInjection;. That namespace will be available if you add "Microsoft.Extensions.DependencyInjection": "1.0.0" to your project.json. Than you should call Init method in your startup class. For example

    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        AppDependencyResolver.Init(app.ApplicationServices);
        //all other code

After that you can use it anywhere, same as DependencyResolver.Current. But my suggestion - use it only if no other choice left.