public Update(User user, Users.List sender)
        {
            InitializeComponent();
            this.txtFirstName.Text = user.FirstName;
            this.txtLastName.Text  = user.LastName;
            this.txtUserName.Text  = user.UserName;
            this._user             = user;
            this._sender           = sender;


            cboRole.ItemsSource   = Enum.GetValues(typeof(Role)).Cast <Role>().ToList();
            cboRole.SelectedValue = user.Role;
        }
        private void btnsave_Click(object sender, RoutedEventArgs e)
        {
            if (Validate() == false)
            {
                return;
            }

            if (UsersBLL.GetDuplicateUserName(txtUserName.Text, this._user.Id) != null)
            {
                MessageBox.Show("Username is already used");
            }
            else
            {
                ShamirasRestaurant.Domain.Models.User user = new ShamirasRestaurant.Domain.Models.User();
                user.Id        = Guid.NewGuid();
                user.UserName  = txtUserName.Text;
                user.LastName  = txtLastName.Text;
                user.FirstName = txtFirstName.Text;

                Role role = new Role();
                if (cboRole.SelectedValue.ToString() == Role.Admin.ToString())
                {
                    role = Role.Admin;
                }
                else if (cboRole.SelectedValue.ToString() == Role.Cashier.ToString())
                {
                    role = Role.Cashier;
                }
                else if (cboRole.SelectedValue.ToString() == Role.Chef.ToString())
                {
                    role = Role.Chef;
                }
                else if (cboRole.SelectedValue.ToString() == Role.InventoryController.ToString())
                {
                    role = Role.InventoryController;
                }
                else if (cboRole.SelectedValue.ToString() == Role.Waiter.ToString())
                {
                    role = Role.Waiter;
                }

                user.Role = role;
                user.Id   = this._user.Id;
                UsersBLL.Update(user);
                MessageBox.Show("User successfully created.");
                this._sender.showList();
                this.Close();
            }
        }