在页面之间切换会导致Windows 10移动版崩溃 [英] Switching between pages causes crashes on Windows 10 Mobile

问题描述

我正在使用Xamarin Forms(2.3.4.247)，而我的应用程序正在使用"HamburgerMenu".要在页面之间切换，我使用的是代码:

I'm using Xamarin Forms (2.3.4.247) and my application is using "HamburgerMenu". To switch between pages i'm using it's code:

private FirstPage firstPage; //it's i get from the constructor
private SecondPage secondPage = new SecondPage();
private ThirdPage thirdPage = new ThirdPage(); 
private async void ItemSelectedMethod()
{
        var root = App.NavigationPage.Navigation.NavigationStack[0];
        if (SelectedItem == Items[0])
        {
            if (!IsFirstChoose)
            {
                App.NavigationPage.Navigation.InsertPageBefore(firstPage, root);
                await App.NavigationPage.PopToRootAsync(false);
            }
        }
        if (SelectedItem == Items[1])
        {
            App.NavigationPage.Navigation.InsertPageBefore(secondPage, root);
            await App.NavigationPage.PopToRootAsync(false);
        }
        if (SelectedItem == Items[2])
        {
            App.NavigationPage.Navigation.InsertPageBefore(thirdPage, root);
            await App.NavigationPage.PopToRootAsync(false);
        }

        IsFirstChoose = false;
        rootPageViewModel.IsPresented = false;
}

在Android和Windows 10桌面上，以及在Windows 10 Mobile模拟器上，一切正常，当我在thirdPage和firstPage之间切换时，我的应用程序崩溃了. FirstPage是根目录:

All working good on Android and Windows 10 desktop, on Windows 10 Mobile simulator my app crashes when I switch between thirdPage and firstPage. FirstPage is root:

FirstPage firstPage = new FirstPage();
NavigationPage = new NavigationPage(firstPage);

我不知道为什么...模拟器不允许调试...

I don't know why... Simulator don't allow debugging...

第二件事: 当我将Xamarin Forms更新到版本2.3.5.256-pre6时，我的应用程序抛出异常"System.ArgumentException:'无法插入导航堆栈中已经存在的页面'" ...但是当我将代码更改为:

The second thing: When I update Xamarin Forms to version 2.3.5.256-pre6 my app throw exception "System.ArgumentException: 'Cannot insert page which is already in the navigation stack'"... But when I change code to:

App.NavigationPage.Navigation.InsertPageBefore(new ThirdPage(), root);
App.NavigationPage.Navigation.InsertPageBefore(new SecondPage(), root);
//etc

所有工作中... 有人知道为什么会这样吗?我不想在切换页面时创建新对象...

all working... Does anyone know why this is happening? I don't want create new objects when pages is switch...

推荐答案

您已经回答了这个问题，所以我只能确认一下:

You have answered the question so I can only confirm this:

System.ArgumentException: 'Cannot insert page which is already in the navigation stack'

如您所见，您已经在App.NavigationPage.Navigation中拥有firstPage页面，因此插入另一个页面会使应用程序崩溃.您只是无法按照说明进行操作-您必须创建一个新实例，或者必须从堆栈中删除以前的实例.

As you can see, you already have the page firstPage in App.NavigationPage.Navigation so inserting another one makes the app crash. You just can't do it as you have explained - either you have to create a new instance or you have to remove previous instance from the stack.

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