How to get current user, and how to use User class in MVC5?

Try something like:

var store = new UserStore<ApplicationUser>(new ApplicationDbContext());
var userManager = new UserManager<ApplicationUser>(store);
ApplicationUser user = userManager.FindByNameAsync(User.Identity.Name).Result;

Works with RTM.

If you're coding in an ASP.NET MVC Controller, use

using Microsoft.AspNet.Identity;

...

User.Identity.GetUserId();

Worth mentioning that User.Identity.IsAuthenticated and User.Identity.Name will work without adding the above mentioned using statement. But GetUserId() won't be present without it.

If you're in a class other than a Controller, use

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

In the default template of MVC 5, user ID is a GUID stored as a string.

No best practice yet, but found some valuable info on extending the user profile:

• Overview of Identity: https://devblogs.microsoft.com/aspnet/introducing-asp-net-identity-a-membership-system-for-asp-net-applications/
• Example solution regarding how to extend the user profile by adding an extra property: https://github.com/rustd/AspnetIdentitySample