AvaloniaProject/AvaloniaApplication4/AdditionalModels/GlobalsData.cs

using Avalonia.Controls;
using AvaloniaApplication4.ViewModels;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AvaloniaApplication4.AdditionalModels
{
    public class GlobalsData : ViewModelBase
    {
        /// <summary>
        /// смена вложенных страниц
        /// </summary>
        UserControl activePage;
        UserControl mainUserControl;

        public GlobalsData()
        {
            this.activePage = new UserControl();
            this.mainUserControl = new UserControl();
        }

        public UserControl GlobalUserControl
        {
            get { return activePage; }
            set
            {
                if (activePage == value)
                    return;

                activePage = value;
                OnPropertyChanged(nameof(GlobalUserControl));
            }
        }
        public UserControl GlobalMainUserControl
        {
            get { return mainUserControl; }
            set
            {
                if (mainUserControl == value)
                    return;

                mainUserControl = value;
                OnPropertyChanged(nameof(GlobalMainUserControl));
            }
        }
    }
}