BackgroundWorker.RunWorkerCompleted

有 2 个全局变量。controlDisable 变量绑定到窗口元素的 IsEnabled 属性。：

private bool completedLogin = true;
    public bool CompletedLogin
    {
        get
        {
            return completedLogin;
        }
        set
        {
            completedLogin = value;
            NotifyPropertyChanged();
        }
    }

private bool controlDisable = true;
    public bool ControlDisable
    {
        get
        {
            return controlDisable;
        }
        set
        {
            controlDisable = value;
            NotifyPropertyChanged();
        }
    }

有一个方法是在另一个线程中单击按钮时执行的（使用的是 BackgroundWorker 类）：

 private RelayCommand loginCommand;

    public RelayCommand LoginCommand
    {
        get
        {
            return loginCommand ??
              (loginCommand = new RelayCommand(obj =>
              {
                  ControlDisable = false;
                  CompletedLogin = false;
                  Password = GetPassword(obj);
                  worker = new BackgroundWorker();
                  worker.DoWork += (obj, ea) => LoginUser();
                  worker.RunWorkerAsync();
                  worker.RunWorkerCompleted += (obj, ea) => OpenGeneral();
              }));
        }
    }

private async void LoginUser()
    {
        if (Login != "" && Password != "")
        {
            using (MSGCoreContext db = new MSGCoreContext())
            {
                user = await db.Users.FirstOrDefaultAsync(u => u.Login == Login);

                if (user != null)
                {
                    userId = user.UserId;
                    userRole = user.Role;

                    if (PBKDF2HashHelper.VerifyPassword(Password, user.Password))
                    {
                        CompletedLogin = true;
                    }
                    else { Warning = "Неверный логин или пароль!"; CompletedLogin = false; ControlDisable = true; }
                }
                else { Warning = "Пользователь не существует!"; CompletedLogin = false; ControlDisable = true; }
            }
        }
        else
        {
            Warning = "Заполните все поля!";
            CompletedLogin = false;
            ControlDisable = true;
        }
    }

在 LoginUser 方法完成执行后，会触发 RunWorkerCompleted 事件，该事件会调用 OpenGeneral 方法：

private void OpenGeneral()
    {
        if (CompletedLogin)
        {
            var displayRootRegistry = (Application.Current as App).displayRootRegistry;
            var dialogWindowViewModel = new GeneralViewModel(Login, userRole);
            displayRootRegistry.ShowPresentation(dialogWindowViewModel);
            Application.Current.MainWindow.Close();
        }
    }

ControlDisable 值已更改，窗口中的元素设置为 IsEnabled = false 状态。而且 OpenGeneral 方法中 CompletedLogin 变量的值总是假的，我怎样才能让 CompletedLogin 的值也改变呢？