Xamarin.Forms Shell 将数据传递到弹出项视图 [英] Xamarin.Forms Shell Passing Data to Flyout Item Views
问题描述
我想知道如何将项目从主 shell 页面传递到弹出页面.或者,我想知道我是否可以在其弹出页面中简单地使用一个对象(它已经存在于主 shell 的范围内).我猜在代码隐藏中有一些方法可以做到这一点.
I would like to know how to pass an item from the main shell page to flyout pages. Or, alternatively, I would like to know if I can simply use an object (which already exists in the scope of the main shell) in its flyout pages. I'm guessing there's some way to do this in the code-behind.
具体来说,我有一个登录页面(它不是 shell 的一部分),一旦用户登录,它就会导航到主 shell.它将 Jason Web 令牌传递给主 shell.所以我在主 shell 中有我需要的东西,我只是不知道如何在弹出页面中使用它!
Specifically, I have a login page (which is not a part of the shell) which navigates to the main shell once a user logs in. It passes a Jason web token to the main shell. So I have what I need in the main shell, I just don't know how to use it in the flyout pages!
这里有一些代码来演示:
Here is some code to demonstrate:
我有一个登录页面,其中的函数接受用户名并将其传递给 shell:
I have a login page with a function that takes a username and passes it to the shell:
async void SignInProcedure(System.Object sender, System.EventArgs e)
{
string name = nameEntry.Text;
if (name == "sally" || name == "Sally")
Application.Current.MainPage = new FlyoutMainShell(name);
else
{
await DisplayAlert("Login", "Login Failed", "Ok");
}
}
当然,我在 shell 的构造函数中有字符串:
And of course, I have the string in the constructor for the shell:
using System;
using System.Collections.Generic;
using System.Windows.Input;
using Xamarin.Forms;
namespace ShellTest
{
public partial class FlyoutMainShell : Shell
{
public FlyoutMainShell(string name)
{
InitializeComponent();
}
}
}
现在我不确定如何在弹出项目page1"和page2"中使用该字符串name",即简单地在页面上显示该名称.
Now I'm not sure how to use that string 'name' in flyout items 'page1' and 'page2', i.e. to simply display that name on the page.
<?xml version="1.0" encoding="UTF-8"?>
<Shell xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="ShellTest.FlyoutMainShell"
xmlns:pages="clr-namespace:ShellTest">
<Shell.FlyoutHeaderTemplate>
<DataTemplate>
<Grid BackgroundColor="Gray" HeightRequest="200">
<Label Text="Here's the header!"
TextColor="White"
FontAttributes="Bold"
HorizontalOptions="Center"
VerticalOptions="Center" />
</Grid>
</DataTemplate>
</Shell.FlyoutHeaderTemplate>
<FlyoutItem x:Name="page1" Title="Go to Page 1">
<ShellContent ContentTemplate="{DataTemplate pages:Page1}"/>
</FlyoutItem>
<FlyoutItem x:Name="page2" Title="Go to Page 2">
<ShellContent ContentTemplate="{DataTemplate pages:Page2}" />
</FlyoutItem>
</Shell>
非常感谢任何帮助!
推荐答案
您可以使用 Xamarin.Essentials: Preferences 将数据存储在 Main Shell 并在page1"和page2"中获取/使用它:
You can use Xamarin.Essentials: Preferences to store the data at Main Shell and get/use it in the 'page1' and 'page2':
在 Main Shell 中,存储数据:
In Main Shell, store the data:
public FlyoutMainShell(string name)
{
InitializeComponent();
Preferences.Set("uesr_name", name);
}
在其他页面,获取值:
public Page1()
{
InitializeComponent();
var myValue = Preferences.Get("uesr_name", "default_value");
}
并且您可以在用户注销时删除该值:
And you can remove the value when the user logout:
Preferences.Remove("uesr_name");
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