1.取消在App.xaml中设置StartUpUrl

2.在后台的APP.Xaml.cs如下设置，先绑定异常处理的handle，再设置StartUpUrl,可以实现在前台设置一样的效果   

public App()        {            App.Current.DispatcherUnhandledException += Current_DispatcherUnhandledException;            AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;            this.StartupUri = new Uri("MainWIndow.xaml", UriKind.Relative);        }        void Current_DispatcherUnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)        {            throw new NotImplementedException();        }        void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)        {            throw new NotImplementedException();        }