Vfrdtyky

I believe you need to reference the current HttpContext if you are outside of the controller. The MVC controllers have a base reference to the current context. However, outside of that, you have to explicitly declare you want the current HttpContext

return HttpContext.Current.GetOwinContext().Authentication;

As for it not showing up, a new MVC 5 project template using the code you show above (the IAuthenticationManager) has the following using statements at the top of the account controller:

using System.Threading.Tasks;

using System.Web;

using System.Web.Mvc;

using Microsoft.AspNet.Identity;

using Microsoft.AspNet.Identity.EntityFramework;

using Microsoft.Owin.Security;

using WebApplication2.Models;

Commenting out each one, it appears the GetOwinContext() is actually a part of the System.Web.Mvc assembly.

After trial and error comparing the using statements of my controller and the Asp.Net Template controller

using System.Web;

Solved the problem for me.
You are also going to need to add:

using Microsoft.AspNet.Identity;

using Microsoft.AspNet.Identity.Owin;

To use GetUserManager method.

Microsoft couldn't find a way to resolve this automatically with right click and resolve like other missing using statements?

in my case adding Microsoft.AspNet.WebApi.Owin refference via nuget did a trick.

Make sure you installed the nuget package Microsoft.AspNet.Identity.Owin. Then add System.Net.Http namespace.

Just using

HttpContext.Current.GetOwinContext()

did the trick in my case.

To get UserManager in API

return HttpContext.Current.GetOwinContext().GetUserManager<AppUserManager>();

where AppUserManager is the class that inherits from UserManager.

I had all the correct packages and usings, but had to built first before I could get GetOwinContext() to work.

For Devs getting this error in Web API Project -

The GetOwinContext extension method is defined in System.Web.Http.Owin dll and one more package will be needed i.e. Microsoft.Owin.Host.SystemWeb. This package needs to be installed in your project from nuget.

Link To Package: OWIN Package Install Command -

Install-Package Microsoft.AspNet.WebApi.Owin    

Link To System.web Package : Package Install Command -

Install-Package Microsoft.Owin.Host.SystemWeb

In order to resolve this error you need to find why its occurring in your case. Please Cross check below points in your code -

1. 
   

   You must have reference to Microsoft.AspNet.Identity.Owin;

   
   
   

   using Microsoft.AspNet.Identity.Owin;

   
   


2. 
   

   Define GetOwinContext() Under HttpContext.Current as below -

   
   
   

    return _userManager1 ?? HttpContext.Current.GetOwinContext().GetUserManager<ApplicationUserManager>();
   
   

   
   
   

   OR

   
   
   

   return _signInManager ?? HttpContext.Current.GetOwinContext().Get<ApplicationSignInManager>();
   
   

   
   

Complete Code Where GetOwinContext() is used -

 public ApplicationSignInManager SignInManager

 {

   get

   {

    return _signInManager ?? HttpContext.Current.GetOwinContext().Get<ApplicationSignInManager>();

   }

    private set

    {

     _signInManager = value;

    }

  }

Namespace's I'm Using in Code File where GetOwinContext() Is used

using AngularJSAuthentication.API.Entities;

using AngularJSAuthentication.API.Models;

using HomeCinema.Common;

using Microsoft.AspNet.Identity;

using Microsoft.AspNet.Identity.EntityFramework;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using System.Web;

using Microsoft.AspNet.Identity.Owin;

using Microsoft.Owin.Security.DataProtection;

I got this error while moving my code from my one project to another.