Prism Library UWP显示应用程序的多个视图

Question

我正在尝试Show multiple views for an app for Prism Library UWP。

我为System.NullReferenceException得到了frame.Navigate(typeof(ScreenCapture));，如下所示：

        async void ExecuteNewWindow()
        {
            CoreApplicationView newView = CoreApplication.CreateNewView();
            int newViewId = 0;
            await newView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                Frame frame = new Frame();
                frame.Navigate(typeof(ScreenCapture));
                Window.Current.Content = frame;
                // You have to activate the window in order to show it later.
                Window.Current.Activate();

                newViewId = ApplicationView.GetForCurrentView().Id;
            });
            bool viewShown = await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newViewId);
        }

如何在uwp的Prism库中实现多视图。

Answer 1

您的项目是Xamarin.Forms，但是var arr = ['messi', 'mo salah']; arr = arr.where( (name) => name != 'messi' ).toList(); // results // arr = ['mo salah']; 的参数是uwp页面类型。我检查了您的代码，frame.Navigate(typeof(ScreenCapture));是表单ScreenCapture。根据您的要求，您可以使用Dependency service来调用ContentPage并将ExecuteNewWindow放入UWP项目中。

界面

ExecuteNewWindow

实施

public interface INewPageService
{
     void  CreateNewPage();
}

用法

[assembly: Dependency(typeof(INewPageService))]

namespace BlankApp1.UWP
{
   public class INewPageServiceImplement : INewPageService
    {
        public async void CreateNewPage()
        {
            CoreApplicationView newView = CoreApplication.CreateNewView();
            int newViewId = 0;
            await newView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                Frame frame = new Frame();
                frame.Navigate(typeof(NewPage)); // uwp page
                Window.Current.Content = frame;
                // You have to activate the window in order to show it later.
                Window.Current.Activate();

                newViewId = ApplicationView.GetForCurrentView().Id;
            });
            bool viewShown = await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newViewId);

         }
    }
}

请不要忘记在uwp app.xaml.cs文件中注册它。

DependencyService.Get<INewPageService>(DependencyFetchTarget.NewInstance).CreateNewPage();