winui侧边栏菜单 打开页面 单页面替换原来的页面 非多选项卡

<?xml version="1.0" encoding="utf-8"?>
<Window
    x:Class="ThaiTong.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:ThaiTong"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Title="ThaiTong">

    <Window.SystemBackdrop>
        <MicaBackdrop />
    </Window.SystemBackdrop>

    <NavigationView IsBackEnabled="True" BackRequested="NavigationView_BackRequested" SelectionChanged="NavigationView_SelectionChanged" IsSettingsVisible="True"  Header="header" PaneTitle="AppError" PaneDisplayMode="Left" >
        <NavigationView.AutoSuggestBox>
            <AutoSuggestBox x:Name="ASB" PlaceholderText="Search" QueryIcon="Find"  QuerySubmitted="QuerySubmitted" SuggestionChosen="SuggestionChosen"/>
        </NavigationView.AutoSuggestBox>
        <NavigationView.MenuItems>
            <NavigationViewItem Icon="Play" Content="1" Tag="SamplePage1"/>
            <NavigationViewItem Icon="Save" Content="2" Tag="SamplePage2">
                <NavigationViewItem.MenuItems>
                    <NavigationViewItem Icon="Print" Content="6" Tag="SamplePage3"/>
                </NavigationViewItem.MenuItems>
            </NavigationViewItem>
            <NavigationViewItem Icon="Refresh" Content="3" Tag="SamplePage3"/>
            <NavigationViewItem Icon="Download" Content="4" Tag="SamplePage4"/>
        </NavigationView.MenuItems>
        <NavigationView.FooterMenuItems>
            <NavigationViewItem Icon="Message" Content="Message" Tag="SamplePage5"/>
        </NavigationView.FooterMenuItems>
        <Frame x:Name="contentFrame"/>
    </NavigationView>
</Window>

using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Controls.Primitives;
using Microsoft.UI.Xaml.Data;
using Microsoft.UI.Xaml.Input;
using Microsoft.UI.Xaml.Media;
using Microsoft.UI.Xaml.Navigation;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.ApplicationSettings;

// To learn more about WinUI, the WinUI project structure,
// and more about our project templates, see: http://aka.ms/winui-project-info.

namespace ThaiTong
{
    /// <summary>
    /// An empty window that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainWindow : Window
    {
        public MainWindow()
        {
            this.InitializeComponent();
            ExtendsContentIntoTitleBar = true;
            SetTitleBar(null);
        }

        private void NavigationView_SelectionChanged(NavigationView sender, NavigationViewSelectionChangedEventArgs args)
        {
            var selectedItem = (NavigationViewItem)args.SelectedItem;
            if (args.IsSettingsSelected)
            {
                contentFrame.Navigate(typeof(SettingsPage));
            }
            if ((string)selectedItem.Tag == "SamplePage1") contentFrame.Navigate(typeof(SamplePage1));
            else if ((string)selectedItem.Tag == "SamplePage2") contentFrame.Navigate(typeof(SamplePage2));
            else if ((string)selectedItem.Tag == "SamplePage3") contentFrame.Navigate(typeof(SamplePage3));
            else if ((string)selectedItem.Tag == "SamplePage4") contentFrame.Navigate(typeof(SamplePage4));
            else if ((string)selectedItem.Tag == "SamplePage5") contentFrame.Navigate(typeof(SamplePage5));
        }
        private void NavigationView_BackRequested(NavigationView sender, NavigationViewBackRequestedEventArgs args)
        {
            if (contentFrame.CanGoBack)
            {
                contentFrame.GoBack();
            }
        }
        private void SuggestionChosen(AutoSuggestBox sender, AutoSuggestBoxSuggestionChosenEventArgs args)
        {
            sender.Text = args.SelectedItem.ToString();
        }
        private void QuerySubmitted(AutoSuggestBox sender, AutoSuggestBoxQuerySubmittedEventArgs args)
        {
            string txt = args.QueryText;  //输入的文本
            if (args.ChosenSuggestion != null)
            {
                //从提示框中选择某一项时触发
            }
            else
            {
                //用户在输入时敲回车或者点击右边按钮确认输入时触发
            }
        }
    }
}