如何在AspNet.Core 2.1中通过依赖注入添加UserManager？

services.AddIdentity<IdentityUser, IdentityRole>()
    .AddEntityFrameworkStores<ApplicationDbContext>()
    .AddDefaultTokenProviders();

services.Configure<IdentityOptions>(options =>
{
    // 设置密码的复杂度要求
    options.Password.RequireDigit = true;
    options.Password.RequireLowercase = true;
    options.Password.RequireUppercase = true;
    options.Password.RequireNonAlphanumeric = false;
    options.Password.RequiredLength = 8;

    // 设置锁定账户策略
    options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(30);
    options.Lockout.MaxFailedAccessAttempts = 5;
});

app.UseAuthentication();

private readonly UserManager<IdentityUser> _userManager;

public YourController(UserManager<IdentityUser> userManager)
{
    _userManager = userManager;
}