MVC 6 IUrlHelper Dependency Injection

ASP.NET Core 2.0

Install

PM> Install-Package AspNetCore.IServiceCollection.AddIUrlHelper

Use

public void ConfigureServices(IServiceCollection services)
{
   ... 
   services.AddUrlHelper();
   ... 
}

Disclaimer: author of this package

This method is now obsolete. Look at update below.

Instead of services.AddTransient<IUrlHelper, UrlHelper>() or trying to directly inject IUrlHelper you can inject IHttpContextAccessor and get the service from there.

public ClassConstructor(IHttpContextAccessor contextAccessor)
{
    this.urlHelper = contextAccessor.HttpContext.RequestServices.GetRequiredService<IUrlHelper>();
}

Unless it is just a bug, adding the IUrlHelper service with UrlHelper does not work.

UPDATE 2017-08-28

The previous method no longer seems to work. Below is a new solution.

Confgure IActionContextAccessor as a service:

public void ConfigureServices(IServiceCollection services)
{
    services
        .AddSingleton<IActionContextAccessor, ActionContextAccessor>()
        .AddMvc();
}

Then inject IActionContextAccessor and IUrlHelperFactory to then generate the IUrlHelper like below

public class MainController : Controller
{
    private IUrlHelperFactory urlHelperFactory { get; }
    private IActionContextAccessor accessor { get; }
    public MainController(IUrlHelperFactory urlHelper, IActionContextAccessor accessor)
    {
        this.urlHelperFactory = urlHelper;
        this.accessor = accessor;
    }

    [HttpGet]
    public IActionResult Index()
    {
        ActionContext context = this.accessor.ActionContext;
        IUrlHelper urlHelper = this.urlHelperFactory.GetUrlHelper(context);
        //Use urlHelper here
        return this.Ok();
    }
}

The UrlHelper requires the current action context, and we can acquire that from the ActionContextAccessor. I'm using this:

        services.AddScoped<IActionContextAccessor, ActionContextAccessor>();
        services.AddScoped<IUrlHelper>(x =>
        {
            var  actionContext = x.GetService<IActionContextAccessor>().ActionContext;
            return new UrlHelper(actionContext);
        });

Now, you can inject IUrlHelper directly into anything that needs it without having to jump through IHttpContextAccessor .