Injection of IUrlHelper in ASP.NET Core

Question

In RC1, IUrlHelper could be injected in services (with services.AddMvc() in startup class)

This doesn't work anymore in RC2. Does anybody know how to do it in RC2 as just newing up a UrlHelper requires an ActionContext object. Don't know how to get that outside a controller.

Answer 1

For ASP.NET Core RC2 there is an issue for this on the github repo. Instead of injecting the IUrlHelper, take an IUrlHelperFactory. It also sounds like you'd need the IActionContextAccessor injected as a Controller no longer has a public property ActionContext.

Register the dependency:

services.AddSingleton<IActionContextAccessor, ActionContextAccessor>();

Then depend on it:

public SomeService(IUrlHelperFactory urlHelperFactory,
                   IActionContextAccessor actionContextAccessor)
{

    var urlHelper =
        urlHelperFactory.GetUrlHelper(actionContextAccessor.ActionContext);
}

Then use it as you see fit.

Answer 2

For Net Core 2.0

Add this after service.AddMvc()

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

Answer 3

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

Answer 4

For .Net Core 2.0

services.AddMvc();

services.AddScoped<IUrlHelper>(x =>
{
   var actionContext = x.GetRequiredService<IActionContextAccessor>().ActionContext;
   var factory = x.GetRequiredService<IUrlHelperFactory>();
   return factory.GetUrlHelper(actionContext);
});

Answer 5

For ASP.Net Core 2.0 you must not inject an IUrlHelper. It’s available as a property of the controller. ControllerBase.Url is an IUrlHelper instance.