sharee.bike-App/ShareeSharedGuiLib/ViewModel/BarLevelInputViewModel.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Windows.Input;
using Xamarin.Forms;

namespace ShareeSharedGuiLib.ViewModel
{
	/// <summary>
	/// Bar based filling level view which shows filling level and allows to edit this level.
	/// </summary>
	public class BarLevelInputViewModel : INotifyPropertyChanged
	{
		public new event PropertyChangedEventHandler PropertyChanged;

		public int? _Maximum = null;

		public int? Maximum
		{
			get => _Maximum;
			set
			{
				if (_Maximum == value)
				{
					// Nothing to do because nothing changed.
					return;
				}

				_Maximum = value;
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(MaximumText)));
			}
		}

		public string MaximumText => Maximum != null
			? Maximum.Value.ToString()
			: string.Empty;

		public int? _Current = null;

		public int? Current
		{
			get => _Current;
			set
			{
				if (_Current == value)
				{
					// Nothing to do because nothing changed.
					return;
				}

				_Current = value;
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Current)));
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(CurrentText)));
			}
		}

		public string CurrentText
		{
			get => Current != null
			? Current.Value.ToString()
			: string.Empty;

			set => Current = int.TryParse(value, out int newCurrent) ? (int?)newCurrent : null;
		}
	}
}