C#

// necessary depending on use
// using NestedClassExample1;

OuterClass1 oc1 = new OuterClass1();

var cat1 = oc1.AddSomething(new Cat("cat1", "meow"));
var cat2 = oc1.AddSomething(new Cat("cat2", "hiss"));
var dog1 = oc1.AddSomething(new Dog("dog1"));

var cat1instance = oc1.GetSomething("cat1");

using System;
using System.Collections.Generic;
using System.Linq;

namespace NestedClassExample1
{
    public interface ISomething1
    {
        string Name { get; }
    }

    public class OuterClass1
    {
        private List<ISomething1> Somethings = new List<ISomething1>();

        internal ISomething1 AddSomething(ISomething1 newsomething)
        {
            Somethings.Add(newsomething);
            return newsomething;
        }

        internal ISomething1 GetSomething(string name)
        {
            return Somethings.FirstOrDefault(smtng => smtng.Name == name);
        }
    }

    public class Cat : ISomething1
    {
        public Cat(string name, string sound = "")
        {
            Name = name;
            CatSound = sound;
        }
        public string Name { get; }
        public string CatSound { set; get; }
    }

    public class Dog : ISomething1
    {
        public Dog(string name, string sound = "")
        {
            Name = name;
            DogSound = sound;
        }

        public string Name { get; }
        public string DogSound { set; get; }
    }

    public class Tiger : ISomething1
    {
        public Tiger(string name) { Name = name; }
        public string Name { get; }
    }
}

System.Exception
  HResult=0x80070490
  Message=Element not found. (0x80070490)
  Source=<Cannot evaluate the exception source>
  StackTrace:
<Cannot evaluate the exception stack trace>

  This exception was originally thrown at this call stack:
    WpfApp1.MainWindow.CreateToastCollection() in MainWindow.xaml.cs
    WpfApp1.MainWindow.MainWindow() in MainWindow.xaml.cs

        private async void SetNotificationCollections()
        {
            string displayName = "Is Potato";
            string launchArg = "NavigateToPotato";
            System.Uri iconURI = new System.Uri("ms-appx:///Assets/icon.png");

<pre>
        ToastCollection licensingManagerToastCollection = new ToastCollection(
            "MyToastCollection",
            displayName,
            launchArg,
            iconURI);

        ToastNotificationManagerForUser defaultManager = ToastNotificationManager.GetDefault();

        try
        {
            ToastCollectionManager collectionManager = defaultManager.GetToastCollectionManager(); //CRASH/exception here.
            await collectionManager.SaveToastCollectionAsync(licensingManagerToastCollection);
        }
        catch
        {
            return;
        }
    }</pre>