为什么有时在.net core mvc应用程序中我的会话值会丢失？

如何解决为什么有时在.net core mvc应用程序中我的会话值会丢失？

我在应用程序（asp.net core mvc）中遇到了一个深层次的问题。直到我进入Asp.net mvc，我才从未发生过这种问题。

会话工作正常，当我在Visual Studio中使用断点检查会话的值时，会话的每个值都会保留。但是，如果我删除断点并仅运行我的应用程序，则会话值将为空/空，并且此问题是间歇性的。我可以认为这是.net core mvc中的一个大缺陷/错误。

我在Session variable value is getting null in ASP.NET Core和Session Lost in Asp.net Core application中检查了很少的答案，但没有一个对我有用。

我在startup.cs中有这些设置

 public void Configure(IApplicationBuilder app,IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                app.UseHsts();
            }

            app.UseAuthentication();
            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();
            app.UseSession();
            app.UseMvc(routes =>
            {
                routes.MapRoute(
                name: "areas",template: "{area:exists}/{controller=Home}/{action=Index}/{id?}");

                routes.MapRoute(
                    name: "default",template: "{controller=Home}/{action=Index}/{id?}");
            });
        }


      services.Configure<CookiePolicyOptions>(options =>
                {
                    // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                    options.CheckConsentNeeded = context => false;
                    options.MinimumSameSitePolicy = SameSiteMode.None;
                });
     services.AddSession(options =>
                {
                    options.IdleTimeout = TimeSpan.FromDays(1);
                });

  services.AddAuthentication(options =>
            {
                options.DefaultScheme = "Cookies";
                options.DefaultChallengeScheme = "oidc";
            }).AddCookie("Cookies",options =>
            {
                // Configure the client application to use sliding sessions
                options.SlidingExpiration = true;
                // Expire the session of 15 minutes of inactivity
                options.ExpireTimeSpan = TimeSpan.FromDays(1);
                if (appSettings.RedisCachingEnabled)
                {
                    options.EventsType = typeof(CustomCookieAuthenticationEvents);
                }
                options.Cookie.HttpOnly = true;
            })

我现在坚持为该项目进行构建，因为最初的会议运行良好。最后，我正在设置并进行这样的会话

UserController.cs类

public IActionResult SetUsers(int id) {
 _sessionData.users= some api call that get users;
  return RedirectToAction("LoadUsers","Home",new
                {
                    area = "Admin",});
}

管理区域/ homeController.cs

 public IActionResult LoadUsers() {
       var users = _sessionData.users;  // some users are lost when trying to get users from session
       // some time its completely null. But if applied breakpoint,it shows correct session                        
 }

这是我的会话课程

public class SessionData : ISessionData
    {
        public IHttpContextAccessor _httpContextAccessor;


        public SessionData(IHttpContextAccessor httpContextAccessor)
        {
            _httpContextAccessor = httpContextAccessor;
        }

        public List<User> users
        {
            get
            {
                var users= _httpContextAccessor.HttpContext.Session.GetObjectFromJson<List<User>>("users");
                if (users == null)
                {
                    users = new List<User>();
                }
                return users;
            }

            set
            {
                _httpContextAccessor.HttpContext.Session.SetObjectAsJson("users",value);
            }
        }

}

解决方法

您可以为IHttpContextAccessor创建自己的扩展方法，以保存json数据或在会话中检索它。 这是一个例子

Type 'ObjectSchema<object & { boolOrString: BooleanSchema<boolean> | StringSchema<string>; }>' is not assignable to type 'ObjectSchema<{ boolOrString: string | boolean; }>'.
  The types of 'fields.boolOrString' are incompatible between these types.
    Type 'Schema<BooleanSchema<boolean> | StringSchema<string>>' is not assignable to type 'Schema<string | boolean>'.
      Type 'BooleanSchema<boolean> | StringSchema<string>' is not assignable to type 'string | boolean'.
        Type 'BooleanSchema<boolean>' is not assignable to type 'string | boolean'.
          Type 'BooleanSchema<boolean>' is not assignable to type 'string'.

并在您的控制器中，将IHttpContextAccessor实例注入构造函数中，您应该能够检索对象并将其保存到会话中

public static class Session
{
        private static IHttpContextAccessor _httpContextAccessor;
        private static ISession _session;

        public static void Initialized(IHttpContextAccessor httpContextAccessor)
        {
            _httpContextAccessor = httpContextAccessor;
            _session = _httpContextAccessor.HttpContext.Session;
        }
        public static bool SetObject(this IHttpContextAccessor httpContextAccessor,string key,object value)
        {
            bool status = false;
            try
            {
                Initialized(httpContextAccessor);
                _session.SetString(key,JsonConvert.SerializeObject(value));

                status = true;
            }
            catch (Exception ex)
            {

            }

            return status;

        }
        public static T GetObject<T>(this IHttpContextAccessor httpContextAccessor,string key)
        {
            try
            {
                Initialized(httpContextAccessor);
                var value = _session.GetString(key);
                return value == null ? default(T) : JsonConvert.DeserializeObject<T>(value);
            }
            catch (Exception ex)
            {
                return default(T);
            }

        }
    
}

用户信息类：

    public class SessionController : Controller
{
    private readonly UserInfo _user;

    public SessionController (IHttpContextAccessor iHttpContextAccessor)
    {
        _user = iHttpContextAccessor.GetObject<UserInfo>("user");//get session with 
                                  //key user 
    }


public IActionResult Login(LoginModel User)
    {
        
                        UserInfo userInfo = new UserInfo
                        {
                            Name = "name",Id = 1
                        };
                        _iHttpContextAccessor.SetObject("user",userInfo);//set 
                                       //userinfo class into session
      }