CommunityToolkit.Mvvm での ViewModel サンプル

MainViewModel.cs

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace MauiApp3 {
    internal class MainViewModel : ObservableObject {

        public RelayCommand IncrementCounterCommand { get; }
        private int Counter;

        public MainViewModel() {
            CounterText = $"Current count: {Counter}";
            IncrementCounterCommand = new RelayCommand(() => CounterText = $"Current count: {++Counter}");
        }

        private string _CounterText;
        public string CounterText { 
            get => _CounterText;
            set => SetProperty(ref _CounterText, value);
        }
    }
}