Change User Id type to int in ASP.NET Identity in VS2015

By default ASP.NET Identity in VS 2015 uses a string as a primary key for AspNet*** tables. I wanted to to use int-typed id's instead. After some research it turned out that different typed id's are supported by the framework out of the box. In the answer below I will show what changes to make to achieve that.

UPDATE: After adding my answer I found this blog post on asp.net site that describes the same but more comprehensive: http://www.asp.net/identity/overview/extensibility/change-primary-key-for-users-in-aspnet-identity

Solution

IdentityModels.cs change to this:

// New derived classes
public class UserRole : IdentityUserRole<int>
{
}

public class UserClaim : IdentityUserClaim<int>
{
}

public class UserLogin : IdentityUserLogin<int>
{
}

public class Role : IdentityRole<int, UserRole>
{
    public Role() { }
    public Role(string name) { Name = name; }
}

public class UserStore : UserStore<ApplicationUser, Role, int,
    UserLogin, UserRole, UserClaim>
{
    public UserStore(ApplicationDbContext context): base(context)
    {
    }
}

public class RoleStore : RoleStore<Role, int, UserRole>
{
    public RoleStore(ApplicationDbContext context): base(context)
    {
    }
}

// You can add profile data for the user by adding more properties to your ApplicationUser class, please visit http://go.microsoft.com/fwlink/?LinkID=317594 to learn more.
public class ApplicationUser : IdentityUser<int, UserLogin, UserRole, UserClaim>
{
    public DateTime? ActiveUntil;

    public async Task<ClaimsIdentity> GenerateUserIdentityAsync(ApplicationUserManager manager)
    {
        // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
        var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
        // Add custom user claims here
        return userIdentity;
    }
}

public class ApplicationDbContext : IdentityDbContext<ApplicationUser, Role, int,
    UserLogin, UserRole, UserClaim>
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }
}

In `App_Start\IdentityConfig.cs, change the following classes:

public class ApplicationUserManager : UserManager<ApplicationUser, int>
{
    public ApplicationUserManager(IUserStore<ApplicationUser, int> store)
        : base(store)
    {
    }

    public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context) 
    {
        var manager = new ApplicationUserManager(new UserStore(context.Get<ApplicationDbContext>()));
        // Configure validation logic for usernames
        manager.UserValidator = new UserValidator<ApplicationUser, int>(manager)
        {
            AllowOnlyAlphanumericUserNames = false,
            RequireUniqueEmail = true
        };

        // Configure validation logic for passwords
        manager.PasswordValidator = new PasswordValidator
        {
            RequiredLength = 8,
            // RequireNonLetterOrDigit = true,
            RequireDigit = true,
            RequireLowercase = true,
            RequireUppercase = true,
        };

        // Configure user lockout defaults
        manager.UserLockoutEnabledByDefault = true;
        manager.DefaultAccountLockoutTimeSpan = TimeSpan.FromMinutes(5);
        manager.MaxFailedAccessAttemptsBeforeLockout = 5;

        // Register two factor authentication providers. This application uses Phone and Emails as a step of receiving a code for verifying the user
        // You can write your own provider and plug it in here.
        manager.RegisterTwoFactorProvider("Phone Code", new PhoneNumberTokenProvider<ApplicationUser, int>
        {
            MessageFormat = "Your security code is {0}"
        });
        manager.RegisterTwoFactorProvider("Email Code", new EmailTokenProvider<ApplicationUser, int>
        {
            Subject = "Security Code",
            BodyFormat = "Your security code is {0}"
        });
        manager.EmailService = new EmailService();
        manager.SmsService = new SmsService();
        var dataProtectionProvider = options.DataProtectionProvider;
        if (dataProtectionProvider != null)
        {
            manager.UserTokenProvider = 
                new DataProtectorTokenProvider<ApplicationUser, int>(dataProtectionProvider.Create("ASP.NET Identity"));
        }
        return manager;
    }
}

// Configure the application sign-in manager which is used in this application.
public class ApplicationSignInManager : SignInManager<ApplicationUser, int>
{
    public ApplicationSignInManager(ApplicationUserManager userManager, IAuthenticationManager authenticationManager)
        : base(userManager, authenticationManager)
    {
    }

    public override Task<ClaimsIdentity> CreateUserIdentityAsync(ApplicationUser user)
    {
        return user.GenerateUserIdentityAsync((ApplicationUserManager)UserManager);
    }

    public static ApplicationSignInManager Create(IdentityFactoryOptions<ApplicationSignInManager> options, IOwinContext context)
    {
        return new ApplicationSignInManager(context.GetUserManager<ApplicationUserManager>(), context.Authentication);
    }
}

In App_Start\Startup.Auth.cs change OnValidateIdentity property to this:

OnValidateIdentity = SecurityStampValidator.OnValidateIdentity<ApplicationUserManager, ApplicationUser, int>(
    validateInterval: TimeSpan.FromMinutes(30),
    regenerateIdentityCallback: (manager, user) => user.GenerateUserIdentityAsync(manager),
    getUserIdCallback: id => id.GetUserId<int>())

Change ManageController to work with the new pk type:

Replace all entries of User.Identity.GetUserId() to User.Identity.GetUserId<int>()

There might be a couple of string id arguments that need to be changed to int, but that's about it.