Avalonia/samples/BindingDemo/ViewModels/MainWindowViewModel.cs

using System;
using System.Collections.ObjectModel;
using System.Linq;
using System.Reactive;
using System.Reactive.Linq;
using System.Threading.Tasks;
using System.Threading;
using MiniMvvm;
using Avalonia.Controls;
using Avalonia.Metadata;
using Avalonia.Controls.Selection;

namespace BindingDemo.ViewModels
{
    public class MainWindowViewModel : ViewModelBase
    {
        private string _booleanString = "True";
        private double _doubleValue = 5.0;
        private string? _stringValue = "Simple Binding";
        private bool _booleanFlag = false;
        private string? _currentTime;
        private NestedCommandViewModel? _nested;

        public MainWindowViewModel()
        {
            Items = new ObservableCollection<TestItem<string>>(
                Enumerable.Range(0, 20).Select(x => new TestItem<string>
                {
                    Value = "Item " + x,
                    Detail = "Item " + x + " details",
                }));

            Selection = new SelectionModel<TestItem<string>> { SingleSelect = false };

            ShuffleItems = MiniCommand.Create(() =>
            {
                var r = new Random();
                Items.Move(r.Next(Items.Count), 1);
            });

            StringValueCommand = MiniCommand.Create<object>(param =>
            {
                BooleanFlag = !BooleanFlag;
                StringValue = param.ToString();
                NestedModel = _nested ?? new NestedCommandViewModel();
            });

            Task.Run(() =>
            {
                while (true)
                {
                    CurrentTime = DateTimeOffset.Now.ToString();
                    Thread.Sleep(1000);
                }
            });

            CurrentTimeObservable = Observable.Timer(TimeSpan.Zero, TimeSpan.FromSeconds(1))
                .Select(x => DateTimeOffset.Now);
        }

        public ObservableCollection<TestItem<string>> Items { get; }
        public SelectionModel<TestItem<string>> Selection { get; }
        public MiniCommand ShuffleItems { get; }

        public string BooleanString
        {
            get { return _booleanString; }
            set { this.RaiseAndSetIfChanged(ref _booleanString, value); }
        }

        public double DoubleValue
        {
            get { return _doubleValue; }
            set { this.RaiseAndSetIfChanged(ref _doubleValue, value); }
        }

        public string? StringValue
        {
            get { return _stringValue; }
            set { this.RaiseAndSetIfChanged(ref _stringValue, value); }
        }

        public bool BooleanFlag
        {
            get { return _booleanFlag; }
            set { this.RaiseAndSetIfChanged(ref _booleanFlag, value); }
        }

        public string? CurrentTime
        {
            get { return _currentTime; }
            private set { this.RaiseAndSetIfChanged(ref _currentTime, value); }
        }

        public IObservable<DateTimeOffset> CurrentTimeObservable { get; }
        public MiniCommand StringValueCommand { get; }

        public DataAnnotationsErrorViewModel DataAnnotationsValidation { get; } = new DataAnnotationsErrorViewModel();
        public ExceptionErrorViewModel ExceptionDataValidation { get; } = new ExceptionErrorViewModel();
        public IndeiErrorViewModel IndeiDataValidation { get; } = new IndeiErrorViewModel();

        public NestedCommandViewModel? NestedModel
        {
            get { return _nested; }
            private set { this.RaiseAndSetIfChanged(ref _nested, value); }
        }

        public void Do(object parameter)
        {

        }

        [DependsOn(nameof(BooleanFlag))]
        bool CanDo(object parameter)
        {
            return BooleanFlag;
        }

        // Nested class, jsut so we can test it in XAML
        public class TestItem<T> : ViewModelBase
        {
            private T? _value;
            private string? _detail;

            public T? Value
            {
                get { return _value; }
                set { this.RaiseAndSetIfChanged(ref this._value, value); }
            }

            public string? Detail
            {
                get { return _detail; }
                set { this.RaiseAndSetIfChanged(ref this._detail, value); }
            }
        }
    }
}