Error No service for type 'Microsoft.AspNetCore.Identity.RoleManager`1[Microsoft.AspNetCore.Identity.IdentityRole]' has been registered

i have this error when i tried to create user and role in the startup file, can you please help me solve this issue. The error is coming from the serviceprovider in this line -----> var roleManager = serviceProvider.GetRequiredService<RoleManager>();

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public class Startup { public Startup(IConfiguration configuration) { Configuration = configuration; }

    public IConfiguration Configuration { get; }        // This method gets called by the runtime. Use this method to add services to the container.      public void ConfigureServices(IServiceCollection services)      {          services.AddControllersWithViews();          services.AddDbContext<LoginDbContext>(options =>                options.UseSqlServer(Configuration.GetConnectionString("LoginConnection")));          //ajouter le service d'authentification Identity          services.AddIdentity<LoginUser, LoginRole>(options =>          {              options.Password.RequiredLength = 6;              options.Password.RequiredUniqueChars = 2;              options.Password.RequireLowercase = false;              options.Password.RequireUppercase = false;              options.Password.RequireNonAlphanumeric = false;              options.Password.RequireDigit = false;              options.SignIn.RequireConfirmedEmail = false;            }).AddEntityFrameworkStores<LoginDbContext>()              .AddDefaultTokenProviders();          services.ConfigureApplicationCookie(options =>          {              options.LoginPath = "/Login/Login";              options.ReturnUrlParameter = "ReturnUrl";              options.LogoutPath = "/Login/Logout";              options.AccessDeniedPath = "/Login/AccessDenied";              options.ExpireTimeSpan = new TimeSpan(0, 15, 0);            });          //ajouter le service MVC          services.AddMvc();      }        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.      public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IServiceProvider serviceProvider)      {          if (env.IsDevelopment())          {              app.UseDeveloperExceptionPage();          }          else          {              app.UseExceptionHandler("/Home/Error");          }          app.UseStaticFiles();            app.UseRouting();            app.UseAuthorization();            app.UseAuthentication();  // ajouter le module d'authentification au middleware mvc            app.UseEndpoints(endpoints =>          {              endpoints.MapControllerRoute(                  name: "default",                  pattern: "{controller=Home}/{action=Index}/{id?}");          });            CreateRoles(serviceProvider);      }        private void CreateRoles(IServiceProvider serviceProvider)      {            var roleManager = serviceProvider.GetRequiredService<RoleManager<IdentityRole>>();          var userManager = serviceProvider.GetRequiredService<UserManager<LoginUser>>();          Task<IdentityResult> roleResult;          string email = "someone@somewhere.com";            //Check that there is an Administrator role and create if not          Task<bool> hasAdminRole = roleManager.RoleExistsAsync("Administrator");          hasAdminRole.Wait();            if (!hasAdminRole.Result)          {              roleResult = roleManager.CreateAsync(new IdentityRole("Administrator"));              roleResult.Wait();          }            //Check if the admin user exists and create it if not          //Add to the Administrator role            Task<LoginUser> testUser = userManager.FindByEmailAsync(email);          testUser.Wait();            if (testUser.Result == null)          {              LoginUser administrator = new LoginUser();              administrator.Email = email;              administrator.UserName = email;                Task<IdentityResult> newUser = userManager.CreateAsync(administrator, "_AStrongP@ssword!");              newUser.Wait();                if (newUser.Result.Succeeded)              {                  Task<IdentityResult> newUserRole = userManager.AddToRoleAsync(administrator, "Administrator");                  newUserRole.Wait();              }          }        }  }**  

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https://stackoverflow.com/questions/66468015/error-no-service-for-type-microsoft-aspnetcore-identity-rolemanager1microsoft March 04, 2021 at 11:09AM