ASP.NET Core Identity

What is ASP.NET Core Identity?

ASP.NET Core Identity is a membership system that adds login functionality, user management, password hashing, roles, claims, and more.

Setting Up Identity

1. Install Package

dotnet add package Microsoft.AspNetCore.Identity.EntityFrameworkCore

2. Create User Model

public class ApplicationUser : IdentityUser
{
    public string? FullName { get; set; }
}

3. Update DbContext

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options) { }
}

4. Configure Services

builder.Services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

builder.Services.AddIdentity<ApplicationUser, IdentityRole>()
    .AddEntityFrameworkStores<ApplicationDbContext>()
    .AddDefaultTokenProviders();

5. Run Migrations

dotnet ef migrations add AddIdentity
dotnet ef database update

User Registration

public class AccountController : Controller
{
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly SignInManager<ApplicationUser> _signInManager;

    [HttpPost]
    public async Task<IActionResult> Register(RegisterViewModel model)
    {
        if (!ModelState.IsValid)
            return View(model);

        var user = new ApplicationUser
        {
            UserName = model.Email,
            Email = model.Email,
            FullName = model.FullName
        };

        var result = await _userManager.CreateAsync(user, model.Password);

        if (result.Succeeded)
        {
            await _signInManager.SignInAsync(user, isPersistent: false);
            return RedirectToAction("Index", "Home");
        }

        foreach (var error in result.Errors)
            ModelState.AddModelError(string.Empty, error.Description);

        return View(model);
    }
}

User Login

[HttpPost]
public async Task<IActionResult> Login(LoginViewModel model)
{
    if (!ModelState.IsValid)
        return View(model);

    var result = await _signInManager.PasswordSignInAsync(
        model.Email, 
        model.Password, 
        model.RememberMe, 
        lockoutOnFailure: false);

    if (result.Succeeded)
        return RedirectToAction("Index", "Home");

    ModelState.AddModelError(string.Empty, "Invalid login attempt");
    return View(model);
}

User Logout

[HttpPost]
public async Task<IActionResult> Logout()
{
    await _signInManager.SignOutAsync();
    return RedirectToAction("Index", "Home");
}

Working with Roles

await _userManager.AddToRoleAsync(user, "Admin");

// Check if user is in role
var isAdmin = await _userManager.IsInRoleAsync(user, "Admin");

Key Takeaways

• ASP.NET Core Identity: Complete membership system
• IdentityUser: Base user class
• IdentityDbContext: DbContext with Identity tables
• UserManager: Manages users (create, update, delete)
• SignInManager: Handles sign-in/sign-out
• Roles: Group users with AddToRoleAsync