ASP.NET Core 2 - Identity - DI errors with custom Roles

Question

I got this code in my Startup.cs:

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

        services.AddIdentity<ApplicationUser, ApplicationRole>()
            .AddEntityFrameworkStores<ApplicationDbContext>()
            .AddDefaultTokenProviders();

In that same file, I also replaced the service.UseIdentity() with app.UseAuthentication(); as recommended by MS in the new version of ASP Core 2.

My Db Context:

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

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
        // Customize the ASP.NET Identity model and override the defaults if needed.
        // For example, you can rename the ASP.NET Identity table names and more.
        // Add your customizations after calling base.OnModelCreating(builder);
    }


    //public DbSet<ApplicationUser> ApplicationUser { get; set; }

    //public DbSet<ApplicationRole> ApplicationRole { get; set; }
}

And my custom Role class:

 public class ApplicationRole : IdentityRole
{
    public ApplicationRole() : base() { }

    public ApplicationRole(string roleName) : base(roleName) { }

    public bool IsDefault { get; set; }
}

When running the application, I got a SeedDatabase helper method that runs:

var roleManager = serviceProvider.GetService<RoleManager<ApplicationRole>>();

This was all working fine, but since updating VS 2017 to the lastest version and installing .NET Core 2.0, this last line of code now throws the following exception:

System.AggregateException occurred
HResult=0x80131500
Message=One or more errors occurred. (Cannot resolve scoped service 'Microsoft.AspNetCore.Identity.RoleManager`1[CspLicensingPortal.Models.ApplicationRole]' from root provider.)
Source=<Cannot evaluate the exception source>
StackTrace:
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at System.Threading.Tasks.Task.Wait()
at CspLicensingPortal.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) in D:\gsandorx\Documents\Visual Studio 2017\Projects\CspLicensingPortal\CspLicensingPortal\Startup.cs:line 275

Inner Exception 1:
InvalidOperationException: Cannot resolve scoped service 'Microsoft.AspNetCore.Identity.RoleManager`1[MyApplication.Models.ApplicationRole]' from root provider.

I'm not sure why the DI service manager is no longer able to find my ApplicationRole class. I have checked and all my references are using this class and not the default IdentityRole.

Any ideas?

Answer 1

You have to create the IServiceScope on your own.

To do this you have to replace

var roleManager = serviceProvider.GetService<RoleManager<ApplicationRole>>();

with

using (IServiceScope scope = app.ApplicationServices.CreateScope()) {
    RoleManager<IdentityRole> roleManager = scope.ServiceProvider.GetRequiredService<RoleManager<IdentityRole>>();

    // Seed database code goes here
}