How to inject userManager inside the DbContext constructor?

Question

I'm using IdentityDbContext and I have a SeedData class that I'm using inside the OnModelCreating method to seed the database using the initial migrations as follows:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);
    //
    //
    SeedData seedData = new(_userManager);
    seedData.SeedWebsiteAdmins(modelBuilder.Entity<WebsiteAdmin>());
    seedData.SeedCompanyAdmins(modelBuilder.Entity<CompanyAdmin>());
    //
    //
}

This SeedData class requires a parameter of type UserManager inside its constructor because it needs to create the new users as follows:

public async void SeedWebsiteAdmins(EntityTypeBuilder<WebsiteAdmin> entity)
{
    var superAdminLogin = new ApplicationUser()
    {
        Name = "Name",
        Email = "Email",
        UserType = UserType.WebsiteAdmin
    };

    var result = await _userManager.CreateAsync(superAdminLogin, "{password}");

    if (result.Succeeded)
    {
        await _userManager.AddToRoleAsync(superAdminLogin, RoleNames.WebsiteAdminRole);
    }

    var superAdmin = new WebsiteAdmin()
    {
        Id = SuperAdminId,
        WebsiteAdminLoginId = superAdminLogin.Id,
        MaxServiceDiscount = 100,

    };

    entity.HasData(superAdmin);
}

I've tried injecting the UserManager inside the DbContext constructor, but it's causing the following error:

System.InvalidOperationException: Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserOnlyStore`3[RepositoryProject.DomainAuth.ApplicationUser,Microsoft.EntityFrameworkCore.DbContext,System.Guid]'

How can I inject the UserManager in the DbContext constructor without causing any error?

Or is there a way to create the identity user without using the UserManager so I can delete the dependency from the SeedData class and hence I wouldn't need it inside the DbContext?

Answer 1

Try this:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    var userManager = this.GetService<UserManager>();
    ...

One thing though, I would do this on your IdentityDbContext implementation using HasData as suggested in one of the comments above NOT in the DbContext OnModelCreating ie.

public MyIdentityDbContext : IdentityDbContext<ApplicationUser, IdentityRole, string> {
    
    public MyIdentityDbContext(DbContextOptions<MyIdentityDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
  
        SetupData(builder);
    }

    private void SetupData(ModelBuilder builder)
    {
        // Users
        var defaultUsers = new List<ApplicationUser>() { 
            new ApplicationUser()
            {
                Id = "USER_HASH"
                Name = "name",
                Email = "[email protected]",
                NormalizedEmail = "[email protected]",
                UserName = "username",
                NormalizedUserName  = "NormalizedUserName",
                UserType = UserType.WebsiteAdmin,
                // Use your known hash here (the hash below is for Password123!)
                PasswordHash = "PasswordHash",
                // Use your hash here
                SecurityStamp = "SecurityStamp",
                AccessFailedCount = 0,
                EmailConfirmed = true,
                PhoneNumberConfirmed = true,
                TwoFactorEnabled = false
            }
        };

        builder.Entity<ApplicationUser>().HasData(defaultUsers);

        // Roles
        var defaultRoles = new List<IdentityRole>(){ 
            new IdentityRole { Id = "ROLE_HASH", Name = 
            RoleNames.WebsiteAdminRole, NormalizedName = 
            RoleNames.WebsiteAdminRole.ToUpper() }
        };

        builder.Entity<IdentityRole>().HasData(defaultRoles);

        // User roles
        var defaultUserRoles = new List<IdentityUserRole<string>>(){ 
            new IdentityUserRole<string>(){
               Id = "USER_HASH",
               RoleId = "ROLE_HASH" 
            }
        };

        builder.Entity<IdentityUserRole<string>>().HasData(defaultUsersRoles);
    }

}

Note: The hash I have for the password above is with API set to use IdentityV3 ie.

builder.Services.Configure<PasswordHasherOptions>(options => options.CompatibilityMode = PasswordHasherCompatibilityMode.IdentityV3);

You can create your own password hash using

var passwordHasher = this.GetService<IPasswordHasher<IdentityUser>>();
var passwordHash = passwordHasher.HashPassword(user, "YourPassword");