avaloniaProject/ViewModels/AutorizationViewModel.cs

using Avalonia.Controls;
using avaloniaPr.Models;
using ReactiveUI;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace avaloniaPr.ViewModels
{
    public class AutorizationViewModel : ViewModelBase
    {
        string textButton = "Далее";
        
        public string TextButton
        {
            get => textButton;
            set => this.RaiseAndSetIfChanged(ref UserData.UserPassword, value);
        }
    }
}