example of todomvc as mvvm w/redux via Uno.CodeGen

MainPageViewModel.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Windows.Input;
using TodoApp.Shared.Models;

namespace TodoApp.Shared.ViewModels
{
	public class MainPageViewModel : INotifyPropertyChanged
	{
		private string _newTodoText;
		private State _state = State.Default;
		private int _filter = 0;

		public MainPageViewModel()
		{
			CreateNew = new SimpleCommand(ExecuteCreateNew);
			ViewAll = new SimpleCommand(() => Filter = 0);
			ViewActive = new SimpleCommand(() => Filter = 1);
			ViewInactive = new SimpleCommand(() => Filter = 2);
		}

		public State State
		{
			get => _state;
			private set
			{
				_state = value;
				OnPropertyChanged();
				OnPropertyChanged(nameof(Todos));
			}
		}

		public int Filter
		{
			get => _filter;
			set
			{
				_filter = value;
				OnPropertyChanged();
				OnPropertyChanged(nameof(Todos));
			}
		} // 0-all, 1-active, 2-inactives

		public IEnumerable<Todo> Todos
		{
			get
			{
				switch (Filter)
				{
					case 0:
						return _state.Todos;
					case 1:
						return _state.ActiveTodos;
					case 2:
						return _state.InactiveTodos;
				}

				throw new InvalidOperationException();
			}
		}

		public string NewTodoText
		{
			get => _newTodoText;
			set
			{
				_newTodoText = value;
				OnPropertyChanged();
			}
		}

		public ICommand CreateNew { get; }

		public ICommand ViewAll { get; }
		public ICommand ViewActive { get; }
		public ICommand ViewInactive { get; }

		private void ExecuteCreateNew()
		{
			var newTodo = new Todo(NewTodoText);
			State = State.WithTodos(todos => todos.Add(newTodo));
			NewTodoText = "";
		}

		public event PropertyChangedEventHandler PropertyChanged;

		protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
		{
			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
		}

		public void ChangeState(Todo todo, bool isDone)
		{
			State = State.WithTodos(todos =>
			{
				var existing = todos.FirstOrDefault(t => t.KeyEquals(todo));
				Todo newTodo = existing.WithIsDone(isDone);
				return newTodo != existing ? todos.Replace(existing, newTodo) : todos;
			});
		}

		public void ChangeText(Todo todo, string newText)
		{
			State = State.WithTodos(todos =>
			{
				var existing = todos.FirstOrDefault(t => t.KeyEquals(todo));
				Todo newTodo = existing.WithText(newText);
				return newTodo != existing ? todos.Replace(existing, newTodo) : todos;
			});
		}

		public void RemoveTodo(Todo todo)
		{
			State = State.WithTodos(todos =>
			{
				var existing = todos.FirstOrDefault(t => t.KeyEquals(todo));
				return existing != null ? todos.Remove(existing) : todos;
			});
		}
	}
}

State.cs

using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using Uno;

namespace TodoApp.Shared.Models
{
    [GeneratedImmutable]
    public partial class State
    {
        [EqualityHash]
        public ImmutableArray<Todo> Todos { get; } = ImmutableArray<Todo>.Empty;

        [EqualityIgnore]
        public int RemainingTodos => ActiveTodos.Count();

        [EqualityIgnore]
        public IEnumerable<Todo> ActiveTodos => Todos.Where(t => !t.IsDone);

        [EqualityIgnore]
        public IEnumerable<Todo> InactiveTodos => Todos.Where(t => t.IsDone);
    }
}

Todo.cs

using System;
using System.Threading;
using Uno;

namespace TodoApp.Shared.Models
{
    [GeneratedImmutable]
    public partial class Todo
    {
        public Todo(string text)
        {
            Text = text;
        }

        [EqualityKey]
        public Guid Id { get; } = Guid.NewGuid();

        public bool IsDone { get; }

        public string Text { get; }
    }
}

See https://github.com/nventive/Uno.CodeGen