Cannot create a DbSet for 'IdentityRole' because this type is not included in the model for the context

This is my AccounController.cs code

        private readonly UserManager<IdentityUser> _userManager;
        private readonly SignInManager<IdentityUser> _signInManager;
        public AccountController(UserManager<IdentityUser> userManager, SignInManager<IdentityUser> signInManager)
        {
            _userManager = userManager;
            _signInManager = signInManager;
        } 

and my login code in AccountController.cs

       [HttpPost]
        public async Task<IActionResult> Login(LoginViewModel model, string returnUrl)
        {
            if (ModelState.IsValid)
            {
                var result = await _signInManager.PasswordSignInAsync(model.Email, model.Password, isPersistent: false, lockoutOnFailure: false);
                if (result.Succeeded)
                {
                  return RedirectToAction("Index", "ArrangeType");
                }
            }
            ModelState.AddModelError("", "Invalid ID or Password");
            return View(model);
        }

When I have run my application this types of error has been occured.

An unhandled exception occurred while processing the request.

InvalidOperationException: Cannot create a DbSet for 'IdentityRole' because this type is not included in the model for the context.

Microsoft.EntityFrameworkCore.Internal.InternalDbSet<TEntity>.get_EntityType()

Answer

Option 1.

Added this and it worked:

builder.Entity<IdentityUserRole<Guid>>().HasKey(p => new { p.UserId, p.RoleId });

Option 2.

The most common reasons for

1. The model name does not match with the table name in database
2. EntityFramework cannot figure out required meta by convention and you have not overriden it.
3. AppDbContext is NOT inherited from DbContext but instead it should be inherited from IdentityDbContext<ApplicationUser>
4. In accountcontroller.cs and startup.cs model doest not match then this types of issue has been occured for example

    public class Role : IdentityRole
    {       
    }

  in your DbContext.cs

    public class DataContext : IdentityDbContext<ApplicationUser, Role, string, IdentityUserClaim<string>, IdentityUserRole<string>,
    IdentityUserLogin<string>, IdentityRoleClaim<string>, IdentityUserToken<string>>
    {
        public DbSet<Role> Role { get; set; }
        public DataContext(DbContextOptions<DataContext> options)
           : base(options)
        {
        } 
    }

in your startup.cs 

  services.AddIdentity<IdentityUser, IdentityRole>();

In the given above there is different Role model so this is not working.You can change startup.cs call 

replace 

services.AddIdentity<IdentityUser, IdentityRole>()

to 

services.AddIdentity<IdentityUser, Role>()

because you have add Role class in your DataContext 

Option 3.

Check that your AppDbContext is NOT inherited from DbContext but instead it should be inherited from IdentityDbContext<ApplicationUser>