如何在.NET 8 IdentityCore中注册UserManager？Blazor Server报错解决

错误信息 #

InvalidOperationException: 无法为类型'StoreManagement.Components.Pages.Users.Users'上的属性'_UserManager'提供值。未注册类型'Microsoft.AspNetCore.Identity.UserManager`1[Microsoft.AspNetCore.Identity.IdentityUser]'的服务。

问题代码 #

Users.razor #

@page "/users"

@using Microsoft.AspNetCore.Authorization;
@using Microsoft.AspNetCore.Identity;

@inject UserManager<IdentityUser> _UserManager
@inject RoleManager<IdentityRole> _RoleManager
@inject AuthenticationStateProvider AuthenticationStateProvider

<h3>Administration</h3>

<AuthorizeView>
    <Authorized>
        @if (@context.User.IsInRole(ADMINISTRATION_ROLE))
        {
            <p>You are in @ADMINISTRATION_ROLE </p>
        }
        else
        {
            <p>You're not signed in as a user in @ADMINISTRATION_ROLE.</p>
        }
    </Authorized>
    <NotAuthorized>
        <p>You're not loggged in.</p>
    </NotAuthorized>
</AuthorizeView>

@code {
    [CascadingParameter]
    private Task<AuthenticationState> authenticationStateTask { get; set; }
    string ADMINISTRATION_ROLE = "Admin";
    System.Security.Claims.ClaimsPrincipal CurrentUser;

    protected override async Task OnInitializedAsync()
    {
        var RoleResult = await _RoleManager.FindByNameAsync(ADMINISTRATION_ROLE);

        if (RoleResult == null)
        {
            await _RoleManager.CreateAsync(new IdentityRole(ADMINISTRATION_ROLE));
        }

        var user = await _UserManager.FindByEmailAsync("exapmle@gmail.com");

        if (user != null)
        {
            var UserResult = await _UserManager.IsInRoleAsync(user, ADMINISTRATION_ROLE);

            if (!UserResult)
            {
                // Put admin in Administrator role
                await _UserManager.AddToRoleAsync(user, ADMINISTRATION_ROLE);
            }
        }

        CurrentUser = (await authenticationStateTask).User;
    }
}

Program.cs #

using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using StoreManagement.Components;
using StoreManagement.Components.Account;
using StoreManagement.Data;
using StoreManagement.Services;

var builder = WebApplication.CreateBuilder(args);

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

builder.Services.AddCascadingAuthenticationState();
builder.Services.AddScoped<IdentityUserAccessor>();
builder.Services.AddScoped<IdentityRedirectManager>();
builder.Services.AddScoped<AuthenticationStateProvider, IdentityRevalidatingAuthenticationStateProvider>();

builder.Services.AddAuthentication(options =>
    {
        options.DefaultScheme = IdentityConstants.ApplicationScheme;
        options.DefaultSignInScheme = IdentityConstants.ExternalScheme;
    })
    .AddIdentityCookies();

var connectionString = builder.Configuration.GetConnectionString("DefaultConnection") ?? throw new InvalidOperationException("Connection string 'DefaultConnection' not found.");
builder.Services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlServer(connectionString));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();

builder.Services.AddIdentityCore<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddRoles<IdentityRole>()
    .AddEntityFrameworkStores<ApplicationDbContext>()
    .AddSignInManager()
    .AddDefaultTokenProviders();

builder.Services.AddSingleton<IEmailSender<ApplicationUser>, EmailSender>();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseMigrationsEndPoint();
}
else
{
    app.UseExceptionHandler("/Error", createScopeForErrors: true);
    app.UseHsts();
}

app.UseHttpsRedirection();

app.UseStaticFiles();
app.UseAntiforgery();

app.MapRazorComponents<App>()
    .AddInteractiveServerRenderMode();

// Add additional endpoints required by the Identity /Account Razor components.
app.MapAdditionalIdentityEndpoints();

app.Run();

解决步骤 #

错误核心是类型不匹配：Program.cs中注册的是UserManager<ApplicationUser>，但组件中注入的是UserManager<IdentityUser>，DI容器找不到对应的服务实例。

1. 修正组件中的注入类型
   将Users.razor中的注入代码修改为：

@inject UserManager<ApplicationUser> _UserManager

2. 确保自定义用户类继承正确
   确认ApplicationUser类继承自IdentityUser：

using Microsoft.AspNetCore.Identity;

namespace StoreManagement.Data;

public class ApplicationUser : IdentityUser
{
    // 可添加自定义属性
}

3. 修正代码拼写错误

• exapmle@gmail.com改为example@gmail.com
• loggged改为logged

内容的提问来源于stack exchange，提问作者Noctious