Shows how to create a helper method to set up binding for multiple properties of a check box.

BindingHelperMethod.cs

using System;
using Eto.Forms;
using Eto.Drawing;
using System.ComponentModel;
using System.Windows.Input;
using System.Linq.Expressions;

namespace MyApp1
{
	public class MyViewModel : INotifyPropertyChanged
	{
		int _prefix1;
		int _prefix2 = 200;
		bool _isChecked1;
		bool _isChecked2 = true;
		bool _isChecked3;

		public int Prefix1
		{
			get { return _prefix1; }
			set
			{
				if (_prefix1 != value)
				{
					_prefix1 = value;
					OnPropertyChanged(nameof(Prefix1));
				}
			}
		}

		public bool IsChecked1
		{
			get { return _isChecked1; }
			set
			{
				if (_isChecked1 != value)
				{
					_isChecked1 = value;
					OnPropertyChanged(nameof(IsChecked1));
				}
			}
		}

		public int Prefix2
		{
			get { return _prefix2; }
			set
			{
				if (_prefix2 != value)
				{
					_prefix2 = value;
					OnPropertyChanged(nameof(Prefix2));
				}
			}
		}

		public bool IsChecked2
		{
			get { return _isChecked2; }
			set
			{
				if (_isChecked2 != value)
				{
					_isChecked2 = value;
					OnPropertyChanged(nameof(IsChecked2));
				}
			}
		}

		public bool IsChecked3
		{
			get { return _isChecked3; }
			set
			{
				if (_isChecked3 != value)
				{
					_isChecked3 = value;
					OnPropertyChanged(nameof(IsChecked3));
				}
			}
		}

		public ICommand DoSomething => new Command((sender, e) =>
		{
			Prefix1++;
			Prefix2--;
			IsChecked1 = !IsChecked1;
			IsChecked2 = !IsChecked2;
			IsChecked3 = !IsChecked3;
		});

		public event PropertyChangedEventHandler PropertyChanged;
		protected void OnPropertyChanged(string propertyName) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
	}

	public class MyPanel : Panel
	{
		CheckBox CreateCheck(string label, Expression<Func<MyViewModel, bool?>> checkedProperty, Expression<Func<MyViewModel, int>> prefixProperty = null)
		{
			var check = new CheckBox();
			if (prefixProperty != null)
				check.BindDataContext(c => c.Text, Binding.Property(prefixProperty).Convert(v => $"({v}) {label}"));
			else
				check.Text = label;
			check.CheckedBinding.BindDataContext(checkedProperty);
			return check;
		}

		public MyPanel()
		{
			var check1 = CreateCheck("Check box 1", m => m.IsChecked1, m => m.Prefix1);
			var check2 = CreateCheck("Check box 2", m => m.IsChecked2, m => m.Prefix2);
			var check3 = CreateCheck("Check box 3", m => m.IsChecked3);

			var doSomethingButton = new Button { Text = "Do Something" };
			doSomethingButton.BindDataContext(c => c.Command, (MyViewModel m) => m.DoSomething);

			Content = new StackLayout
			{
				Items =
				{
					check1,
					check2,
					check3,
					doSomethingButton
				}
			};

			DataContext = new MyViewModel();
		}
	}

	/// <summary>
	/// Your application's main form
	/// </summary>
	public class MainForm : Form
	{
		public MainForm()
		{
			Title = "My Eto Form";
			ClientSize = new Size(400, 350);

			Content = new MyPanel();

		}
	}
}