Get the user id of a username identity 2.0

Question

MVC 5 with asp.net identity 2.0

I understand how to get the currently logged in user id. I have a need to get the user id of a different user in the system. How is this done?

Ex. I need to get the user id of user names "fsmith" ...

Answer 1

Inside the AccountController you can call the following method to get user object and then get the User Id.

var user = await UserManager.FindByNameAsync(userName);
var userId = user.Id;

If you are not inside AccountController you can get the UserManager reference using the following code

var UserManager = HttpContext.GetOwinContext().GetUserManager<ApplicationUserManager>();

Answer 2

To add to Shashi's useful answer...

If you're inside the account controller you can use the existing UserManager:

var user = await UserManager.FindByNameAsync(userName);
var userId = user.Id;

In other controllers (and maybe select other places where HttpContext is available) you create a User Manager with:

var um = HttpContext.GetOwinContext().GetUserManager<ApplicationUserManager>();

But what it took me a while to realize is you can get at it just about anywhere with this last bit. For instance I used it in my seed method (in Configuration.cs) so I could seed the User property of another model:

var um = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(*insert-your-db-context-here*));

Answer 3

One way would to use the FindByNameAsync method of your user manager (or the generic version of it). It takes the name of the user (in your case "fsmith") and returns a task of a user object. This user object contains all the information available about that user.

A code snippet could look similar to the following one (if you're looking for the database ID):

var user = await UserManager.FindByNameAsync("fsmith");
var userId = user.Id;

EDIT

The UserManager instance is normally declared as follows (keep in mind that there are many ways of declaring it, for example when using Dependency Injection):

public AccountController()
  : this(new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new ApplicationDbContext())))
{
}

public AccountController(UserManager<ApplicationUser> userManager)
{
  UserManager = userManager;
}

public UserManager<ApplicationUser> UserManager { get; private set; }