public void DeleteCitizen(bool confirm)
        {
            Name.Text      = "";
            FirstName.Text = "";

            try
            {
                Int32 id = Convert.ToInt32(CitizenID.Text);

                Citizen citizen = DeleteUser.Read_CitizenID(id);
                Name.Text      = citizen.name;
                FirstName.Text = citizen.firstName;

                if (confirm == true)
                {
                    Delete(citizen);
                }

                // TEST
                if (DeleteUser.Read_CitizenID(id) == null)
                {
                    Console.WriteLine("Löschen erfolgreich");
                    number.Opacity = 0;
                }
                else
                {
                    Console.WriteLine("Löschen NICHT erfolgreich");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Fehler beim Löschen:" + ex.Message);
                number.Opacity = 1;
            }
        }
        private void TabItem_MouseUp_1(object sender, MouseButtonEventArgs e)
        {
            DeleteUser del = new DeleteUser();
            DeleteUser AddTaskUserControl = new DeleteUser();

            DockPanel.SetDock(AddTaskUserControl, Dock.Top);
            SwitchContainer.Children.Clear();
            SwitchContainer.Children.Add(AddTaskUserControl);
        }
        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            DeleteUser del = new DeleteUser();
            DeleteUser AddTaskUserControl = new DeleteUser();

            DockPanel.SetDock(AddTaskUserControl, Dock.Top);
            SwitchContainer.Children.Clear();
            SwitchContainer.Children.Add(AddTaskUserControl);
        }