初始化 .NET 8 Blazor Web 应用程序中的角色

Question

我正在尝试初始化 Blazor 应用程序的角色。这是我的服务，如果角色不存在，应该创建角色：

using Microsoft.AspNetCore.Identity;

namespace FoodApp.Services
{
    public class RoleInitializerService : IHostedService
    {
        private readonly RoleManager<IdentityRole> _roleManager;

        public RoleInitializerService(RoleManager<IdentityRole> roleManager)
        {
            _roleManager = roleManager;
        }

        public async Task StartAsync(CancellationToken cancellationToken)
        {
            string[] roles = { "Administrator", "User" };

            foreach (var role in roles)
            {
                if (!await _roleManager.RoleExistsAsync(role))
                {
                    await _roleManager.CreateAsync(new IdentityRole(role));
                }
            }
        }

        public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
    }
}

这是program.cs中的服务注册

builder.Services.AddScoped<RoleInitializerService>();

我在服务的

StartAsync

方法中放置了一个断点，但该方法从未执行过。

我做错了什么？问题在于生命周期不匹配还是其他什么？

Answer 1

你可以尝试这个代码：

using Microsoft.AspNetCore.Identity;
   using Microsoft.Extensions.Hosting;
   using System.Threading;
   using System.Threading.Tasks;

   namespace FoodApp.Services
   {
       public class RoleInitializerService : IHostedService
       {
           private readonly RoleManager<IdentityRole> _roleManager;

           public RoleInitializerService(RoleManager<IdentityRole> roleManager)
           {
               _roleManager = roleManager;
           }

           public async Task StartAsync(CancellationToken cancellationToken)
           {
               string[] roles = { "Administrator", "User" };

               foreach (var role in roles)
               {
                   if (!await _roleManager.RoleExistsAsync(role))
                   {
                       await _roleManager.CreateAsync(new IdentityRole(role));
                   }
               }
           }

           public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
       }
   }

程序.cs：

 var builder = WebApplication.CreateBuilder(args);

   // Add services to the container.
   builder.Services.AddControllersWithViews();

   // Register RoleManager and Identity services
   builder.Services.AddIdentity<IdentityUser, IdentityRole>()
       .AddEntityFrameworkStores<ApplicationDbContext>()
       .AddDefaultTokenProviders();

   // Register the RoleInitializerService as a hosted service
   builder.Services.AddHostedService<RoleInitializerService>();

   var app = builder.Build();

   // Configure the HTTP request pipeline.
   if (!app.Environment.IsDevelopment())
   {
       app.UseExceptionHandler("/Home/Error");
       app.UseHsts();
   }

   app.UseHttpsRedirection();
   app.UseStaticFiles();

   app.UseRouting();

   app.UseAuthentication();
   app.UseAuthorization();

   app.MapControllerRoute(
       name: "default",
       pattern: "{controller=Home}/{action=Index}/{id?}");

   app.Run();