Question

我有两页MainPage和SecondPage1 .in App.xaml.cs我使用以下代码导航到Secondpage1： App.xaml.cs：

//MainPage = new  Fmkt44Application.MainPage();/*First Approach*/
  MainPage = new NavigationPage(new MainPage());/*Second approach*/

MainPage.xaml.cs中：

// App.Current.MainPage = new NavigationPage(new SecondPage1());/*First Approach*/
await Navigation.PushAsync(new SecondPage1());/*Second approach*/

问题是，如果我使用这两种方法，我可以导航到secondpage1，但如果我使用第二种方法，我无法写入搜索栏或任何条目。是什么原因以及如何解决？

这是MainPage.xaml.cs

namespace Fmkt44Application
{
 public partial class MainPage : ContentPage
 {
  public MainPage()
    {
        InitializeComponent();
    }
    public async System.Threading.Tasks.Task LoginControlAsync(Object sender, EventArgs args)
    {
        User.UserName = entry_user.Text;
        User.Password = entry_passw.Text;
        if (User.CheckUserInformation() == false)
        {
            DisplayAlert("Login", "Kullanıcı Adını veya şifresini giriniz", "OK");
        }
        else
        {
            String val = entry_user.Text + "$" + entry_passw.Text;
            CallIasWebService.Login();
            String rval = CallIasWebService.CallIASService("PROFILECONTROL", val);
            CallIasWebService.Logout();
            User.Profile = rval.ToString();

            if (rval != "0"  )
            {
                if (User.Profile != "" && User.Profile != null)
                {

                    // App.Current.MainPage = new NavigationPage(new SecondPage1());if I Call Like this I can write on Secondpage1 (First approach)
                    await Navigation.PushAsync(new SecondPage1());/*I cannot reach SecondPage1 controls/* (second approach)*/
                }
                    else
                {
                    DisplayAlert("Login", "Kayıt yapma yetkiniz yoktur.", "OK");
                }

            }
            else
            {
                DisplayAlert("Login", "Kullanıcı Adını veya şifresi hatalıdır.", "OK");

            }
        }

    }
    public async System.Threading.Tasks.Task scanncontrolAsync(Object sender, EventArgs E)
    {
      // await Navigation.PushAsync(new SecondPage1());
        App.Current.MainPage = new SecondPage1();
    }
}

}

App.cs是

    public App ()
    {
        InitializeComponent();

        //MainPage = new  Fmkt44Application.MainPage();(First apploach)
         MainPage = new NavigationPage(new MainPage());/*second approach*/

    }

Secondpage1.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="Fmkt44Application.SecondPage1">
<ContentPage.Content>
    <StackLayout>
        <SearchBar Placeholder="Ara..." TextChanged="TextChange" x:Name="searchbar" />
        <ListView x:Name="Materials" ItemTapped="MakineSec" HasUnevenRows="True">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <StackLayout>
                                <StackLayout Orientation="Horizontal"  >
                                    <Label Text="{Binding Material}"/>
                                    <Label Text="{Binding Stext}"/>
                                </StackLayout>
                                <Entry Text="{Binding SerialNumber}" />
                            </StackLayout>
                            <ViewCell.ContextActions>
                                <MenuItem Text="Seç" Clicked="MakineSec" CommandParameter="{Binding .}"/>
                            </ViewCell.ContextActions>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
     </StackLayout>
</ContentPage.Content>

Answer 1

问题来自Android模拟器。我尝试了一个真正的平板电脑问题。

Xamarin表单导航页面搜索栏条目无法写入

1 个答案: