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
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。
我正在从 app.xaml.cs
像这样打开主页 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:
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>();
}
}
}
当我尝试从菜单导航到 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。
解决方法
更新:
除了我在问题中已修复的旧答案之外,根据 this,Prism 8 似乎不支持 FlyoutPage。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
试过你的例子,对我来说效果很好:
<?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:
似乎您没有将任何参数传递给您的 NavigateCommand
。试试这个
<StackLayout>
<Button Text="Page2" HeightRequest="50" WidthRequest="100" Command="{Binding NavigateCommand}" CommandParameter="Page2"></Button>
</StackLayout>