UWP打印支持应用（Print Support App）中虚拟打印机无法显示的问题求助

各位大佬好，我是第一次尝试开发UWP的打印支持应用（Print Support App），目标是做一个能在Windows打印对话框里选中的虚拟打印机（命名为MyCustomPrinter，配置在Package.appxmanifest里），但现在打印机完全没出现在设备列表里。微软的Print Support App设计文档看得我一头雾水，完全摸不着门路，实在没办法了来求助大家。

我是用Visual Studio 2022创建的「Blank App (Universal Windows)」项目，现在把我目前的代码和配置都贴出来，麻烦帮我看看哪里出问题了，有没有遗漏什么关键配置？

App.xaml #

<Application x:Class="PrintingApp.App" 
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
             xmlns:local="using:PrintingApp">
</Application>

App.xaml.cs #

using Windows.ApplicationModel.Activation;
using Windows.Foundation;
using Windows.Graphics.Printing.PrintSupport;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace PrintingApp
{
    /// <summary>
    /// Provides application-specific behavior to supplement the default <see cref="Application"/> class.
    /// </summary>
    sealed partial class App : Application
    {
        Deferral settingsDeferral;

        protected override void OnActivated(IActivatedEventArgs args)
        {
            if (args.Kind == ActivationKind.PrintSupportSettingsUI)
            {
                // Get the activation arguments
                var settingsEventArgs = args as PrintSupportSettingsActivatedEventArgs;
                PrintSupportSettingsUISession settingsSession = settingsEventArgs.Session;

                // Take deferral
                this.settingsDeferral = settingsEventArgs.GetDeferral();

                // Create root frame
                var rootFrame = new Frame();

                // Choose the page to be shown based upon where the application is being launched from
                switch (settingsSession.LaunchKind)
                {
                    case SettingsLaunchKind.UserDefaultPrintTicket:
                    {
                        // Show settings page when launched for default printer settings
                        rootFrame.Navigate(typeof(DefaultSettingsView), settingsSession);
                    }
                    break;
                    case SettingsLaunchKind.JobPrintTicket:
                    {
                        // Show settings page when launched from printing app
                        rootFrame.Navigate(typeof(MainPage), settingsSession);
                    }
                    break;
                }

                Window.Current.Content = rootFrame;
            }
        }

        internal void ExitSettings()
        {
            settingsDeferral.Complete();
        }
    }
}

Package.appxmanifest #

<?xml version="1.0" encoding="utf-8"?>
<Package xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10" 
         xmlns:mp="http://schemas.microsoft.com/appx/2014/phone/manifest" 
         xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10" 
         xmlns:uap11="http://schemas.microsoft.com/appx/manifest/uap/windows10/11" 
         xmlns:printsupport="http://schemas.microsoft.com/appx/manifest/printsupport/windows10" 
         xmlns:printsupport2="http://schemas.microsoft.com/appx/manifest/printsupport/windows10/2" 
         xmlns:desktop4="http://schemas.microsoft.com/appx/manifest/desktop/windows10/4" 
         xmlns:iot2="http://schemas.microsoft.com/appx/manifest/iot/windows10/2" 
         IgnorableNamespaces="uap mp desktop4 iot2 printsupport printsupport2 uap11">
  <Identity Name="bc0e7b39-aec8-4569-85ad-b42b6da40308" 
            Publisher="CN=CrazyEight" 
            Version="1.0.0.0" />
  <mp:PhoneIdentity PhoneProductId="bc0e7b39-aec8-4569-85ad-b42b6da40308" 
                     PhonePublisherId="00000000-0000-0000-0000-000000000000"/>
  <Properties>
    <DisplayName>PrintingApp</DisplayName>
    <PublisherDisplayName>CrazyEight</PublisherDisplayName>
    <Logo>Assets\StoreLogo.png</Logo>
  </Properties>
  <Dependencies>
    <TargetDeviceFamily Name="Windows.Universal" 
                        MinVersion="10.0.0.0" 
                        MaxVersionTested="10.0.0.0" />
  </Dependencies>
  <Resources>
    <Resource Language="x-generate"/>
  </Resources>
  <Applications>
    <Application Id="App" 
                 Executable="$targetnametoken$.exe" 
                 EntryPoint="PrintingApp.App" 
                 desktop4:SupportsMultipleInstances="true" 
                 iot2:SupportsMultipleInstances="true">
      <uap:VisualElements DisplayName="PrintingApp" 
                          Square150x150Logo="Assets\Square150x150Logo.png" 
                          Square44x44Logo="Assets\Square44x44Logo.png" 
                          Description="PrintingApp" 
                          BackgroundColor="transparent">
        <uap:DefaultTile Wide310x150Logo="Assets\Wide310x150Logo.png"/>
        <uap:SplashScreen Image="Assets\SplashScreen.png" />
      </uap:VisualElements>

（注：我的Package.appxmanifest内容可能有点截断，但关键配置部分应该都在上面了）

麻烦各位帮我看看，是不是哪里没配置对，或者少了什么必须的步骤才导致虚拟打印机不显示？谢谢大家了！

内容来源于stack exchange