本地IdentityServer4通過OpenIdConnect第一次訪問站點時需要注冊一個新用戶。找到了在OnUserInformationReceived事件中執行此操作的“最佳位置” ，但不確定如何在事件處理程序（啟動類）中訪問 EF DbContext。沒有用于獲取 DbContext 的預配置實例（在其構造函數中請求其他依賴項）的 DI。public void ConfigureServices(IServiceCollection services){    // ...    services.AddAuthentication(options =>        {            options.DefaultScheme = "Cookies";            options.DefaultChallengeScheme = "oidc";        })        .AddCookie("Cookies")        .AddOpenIdConnect("oidc", options =>        {            options.SignInScheme = "Cookies";            // ...            options.Events.OnUserInformationReceived = OnUserInformationReceived;        });    // ...}private Task OnUserInformationReceived(UserInformationReceivedContext c){    var userId = c.User.Value<string>(JwtRegisteredClaimNames.Sub);    // Call DbContext to insert User entry if doesn't exist.    // Or there is another place to do that?    return Task.CompletedTask;}