Ellbar Ellbar - 3 months ago 114
C# Question

ASP MVC5 - Identity. How to get current ApplicationUser

I have Article entity in my project which have

ApplicationUser
property named
Author
. How can I get full object of currently logged
ApplicationUser
. While creating new article I have to set
Author
property in
Article
to current
ApplicationUser
.

In old Membership mechanism it was simple but in the new Identity approach I don't know how to do this.

I tried to do this that way:


  • Add using statement for Identity extensions:
    using Microsoft.AspNet.Identity;

  • Then I try to get current user:
    ApplicationUser currentUser = db.Users.FirstOrDefault(x => x.Id == User.Identity.GetUserId());



But I get exception :


LINQ to Entities does not recognize the method 'System.String GetUserId(System.Security.Principal.IIdentity)' method, and this method cannot be translated into a store expression.
Source=EntityFramework

Answer

You should not need to query the database directly for the current ApplicationUser.

That introduces a new dependency of having an extra context for starters, but going forward the user database tables change (3 times in the past 2 years) but the API is consistent. For example the users table is now called AspNetUsers in Identity Framework, and the names of several primary key fields kept changing, so the code in several answers will no longer work as-is.

Another problem is that the underlying OWIN access to the database will use a separate context, so changes from separate SQL access can produce invalid results (e.g. not seeing changes made to the database). Again the solution is to work with the supplied API and not try to work-around it.

The correct way to access the current user object in ASP.Net identity (as at this date) is:

var user = UserManager.FindById(User.Identity.GetUserId());

or, if you have an async action, something like:

var user = await UserManager.FindByIdAsync(User.Identity.GetUserId());

FindById requires you have the following using statement so that the non-async UserManager methods are available (they are extension methods for UserManager, so if you do not include this you will only see FindByIdAsync):

using Microsoft.AspNet.Identity;

If you are not in a controller at all (e.g. you are using IOC injection), then the user id is retrieved in full from:

System.Web.HttpContext.Current.User.Identity.GetUserId();

If you are not in the standard Account controller you will need to add the following (as an example) to your controller:

1. Add these two properties:

    /// <summary>
    /// Application DB context
    /// </summary>
    protected ApplicationDbContext ApplicationDbContext { get; set; }

    /// <summary>
    /// User manager - attached to application DB context
    /// </summary>
    protected UserManager<ApplicationUser> UserManager { get; set; }

2. Add this in the Controller's constructor:

    this.ApplicationDbContext = new ApplicationDbContext();
    this.UserManager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(this.ApplicationDbContext));

Update March 2015

Note: The most recent update to Identity framework changes one of the underlying classes used for authentication. You can now access it from the Owin Context of the current HttpContent.

ApplicationUser user = System.Web.HttpContext.Current.GetOwinContext().GetUserManager<ApplicationUserManager>().FindById(System.Web.HttpContext.Current.User.Identity.GetUserId());

Addendum:

When using EF and Identity Framework with Azure, over a remote database connection (e.g. local host testing to Azure database), you can randomly hit the dreaded “error: 19 - Physical connection is not usable”. As the cause is buried away inside Identity Framework, where you cannot add retries (or what appears to be a missing .Include(x->someTable)), you need to implement a custom SqlAzureExecutionStrategy in your project.