MainWindow构造函数被调用两次

我正在尝试将MainWindowDataContext设置为App.OnStartup ViewModel。 我注意到,当这样做时, MainWindow()构造函数被调用两次,我看到打开了2个窗口。 有什么想法导致这种行为吗? 我的代码如下:

 public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e); MainWindow mainWindow = new MainWindow(); // Create the ViewModel to which the main window binds. MainWindowViewModel mainWindowViewModel = new MainWindowViewModel(); // Register handle such that when the mainWindowViewModel asks to be closed, close the window. mainWindowViewModel.RequestClose += delegate(System.Object o, System.EventArgs eventArgs) { mainWindow.Close(); }; mainWindow.DataContext = mainWindowViewModel; mainWindow.Show(); } } 

App.xaml仍然存在StartupUri ,我怀疑…