Manager.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;

namespace kurs
{
    static class Manager
    {
        public static Frame MainFrame { get; set; }
        static UserData _currentUser = null;
        public static UserData CurrentUser {
            get => _currentUser;
            set {
                _currentUser = value;
                NotifyUserChange(value);
            }
        }
                
        public delegate void UserChangeHandler(UserData user);
        public static event UserChangeHandler UserChangeEvent;
        private static void NotifyUserChange(UserData user)
        {
            UserChangeEvent?.Invoke(user);
        }

        public static bool TrySaveOrShowErrorMessage()
        {
            try
            {
                Dns2Entities.GetContext().SaveChanges();
                return true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.ToString(), "Error saving changes to db", MessageBoxButton.OK, MessageBoxImage.Error);
                return false;
            }
        }

        public static void SaveOrShowErrorMessage()
        {
            try
            {
                Dns2Entities.GetContext().SaveChanges();
            }
            catch (Exception e)
            {
                MessageBox.Show(e.ToString(), "Error saving changes to db", MessageBoxButton.OK, MessageBoxImage.Error);
                throw e;
            }
        }
    }
}