WPF手动关闭Windows窗体

Dispatcher  不能挂多线程

Application.Current.Dispatcher.BeginInvoke(new Action(() =>
                    {
                        try
                        {
                            int count = 0;
                            foreach (Window window in Application.Current.Windows)
                            {
                                if (window.GetType() == typeof(LogInWindow))
                                {
                                    this.Num=10;
                                    window.Close();
                                }
                            }
                        }
                        catch (Exception ex)
                        {
                            NLogger.LogError(ex);
                        }
                    }));