Xamarin.Forms FlyoutPage 不适用于 Prism [英] Xamarin.Forms FlyoutPage is not working with Prism

问题描述

请帮帮我.为了让您理解我的问题，我在示例应用程序中复制了该场景

Please help me out. In order for you to understand my problem, I have replicated the scenario in sample application

由于 Xamarin.Forms 在 5.0 版本中引入了 FlyoutPage 页面，导航在其中一个应用程序中不起作用.我从 app.xaml.cs 像这样打开主页 await NavigationService.NavigateAsync("Page3");

As Xamarin.Forms introduced FlyoutPage page in 5.0 version, navigation is not working in one of the applications. I am opening main page from app.xaml.cs like this await NavigationService.NavigateAsync("Page3");

弹出页面:

    <FlyoutPage xmlns="http://xamarin.com/schemas/2014/forms"
                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                xmlns:views="clr-namespace:PrismNavigation.Views;assembly=PrismNavigation"
                xmlns:prism="http://prismlibrary.com"
                prism:ViewModelLocator.AutowireViewModel="True"
                x:Class="PrismNavigation.Views.Page3"
                Title="Master">
        <FlyoutPage.Flyout>
            <ContentPage Title="Menu">
                <StackLayout>
                <Button Text="Page2" HeightRequest="50" WidthRequest="100" Command="{Binding NavigateCommand}" CommandParameter="Page2"></Button>
                </StackLayout>
            </ContentPage>
        </FlyoutPage.Flyout>
        <FlyoutPage.Detail>
            <NavigationPage>
                <x:Arguments>
                    <views:Page1></views:Page1>
                </x:Arguments>
            </NavigationPage>
        </FlyoutPage.Detail>
    </FlyoutPage>

Page3ViewModel:

Page3ViewModel:

    using Prism.Commands;
    using Prism.Mvvm;
    using Prism.Navigation;
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    
    namespace PrismNavigation.ViewModels
    {
        public class Page3ViewModel : ViewModelBase
        {
            private readonly INavigationService navigationService;
    
            public Page3ViewModel(
                INavigationService navigationService)
                : base(navigationService)
            {
                this.navigationService = navigationService;
                this.NavigateCommand = new DelegateCommand<string>(this.NavigateCommandExecute);
            }
    
            public override void OnNavigatedTo(INavigationParameters parameters)
            {
                base.OnNavigatedTo(parameters);
            }
    
            private void NavigateCommandExecute(string obj)
            {
                this.navigationService.NavigateAsync($"NavigationPage/{obj}");
            }
    
            public DelegateCommand<string> NavigateCommand { get; set; }
        }
    }

应用:

    using Prism;
    using Prism.Ioc;
    using PrismNavigation.ViewModels;
    using PrismNavigation.Views;
    using Xamarin.Essentials.Implementation;
    using Xamarin.Essentials.Interfaces;
    using Xamarin.Forms;
    
    namespace PrismNavigation
    {
        public partial class App
        {
            public App(IPlatformInitializer initializer)
                : base(initializer)
            {
            }
    
            protected override async void OnInitialized()
            {
                InitializeComponent();
                await NavigationService.NavigateAsync("Page3");
            }
    
            protected override void RegisterTypes(IContainerRegistry containerRegistry)
            {
                containerRegistry.RegisterSingleton<IAppInfo, AppInfoImplementation>();
    
                containerRegistry.RegisterForNavigation<NavigationPage>();              
                containerRegistry.RegisterForNavigation<Page1>();
                containerRegistry.RegisterForNavigation<Page2>();
                containerRegistry.RegisterForNavigation<Page3, Page3ViewModel>();
            }
        }
    }

当我试图从菜单导航到 Page2 时，我不能这样做.当我点击按钮时，导航命令被执行，但导航没有发生.

When I am trying to navigate to Page2 from menu, i can not do that. When I click the button, navigate command is executed, but navigation is not happening.

推荐答案

更新:除了我在问题中修复的旧答案之外，根据 这个.计划用于 8.1.因此，您可以等待 8.1 或将其替换为 MasterDetailPage.我用 MasterDetailPage 尝试了你的例子，它对我来说很好:

Update: In addition to my old answer, which you have fixed in the question, it seems that the FlyoutPage is not supported by Prism 8 according to this. It is planned for 8.1. So, you can either wait 8.1 or replace it with MasterDetailPage. I tried your example with MasterDetailPage and it worked fine for me:

<?xml version="1.0" encoding="utf-8" ?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"
                  xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                  xmlns:prism="http://prismlibrary.com"
                  prism:ViewModelLocator.AutowireViewModel="True"
                  x:Class="PrismNavigation.Views.Page3">

    <MasterDetailPage.Master>
        <ContentPage Title="Menu">
            <StackLayout Padding="20">
                <Button Text="Page2" HeightRequest="50" WidthRequest="100" Command="{Binding NavigateCommand}" CommandParameter="Page2"></Button>
            </StackLayout>
        </ContentPage>
    </MasterDetailPage.Master>
    
    <MasterDetailPage.Detail>
      <NavigationPage>
        <x:Arguments>
            <ContentPage Title="This is Page1"></ContentPage>
        </x:Arguments>
      </NavigationPage>
    </MasterDetailPage.Detail>
    
</MasterDetailPage>

旧答案:似乎您没有向 NavigateCommand 传递任何参数.试试这个

Old answer: Seems like you didn't pass any parameter to your NavigateCommand. Try this

<StackLayout>
    <Button Text="Page2" HeightRequest="50" WidthRequest="100" Command="{Binding NavigateCommand}" CommandParameter="Page2"></Button>
</StackLayout>

这篇关于Xamarin.Forms FlyoutPage 不适用于 Prism的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！