private void btnEditChoroba_Click(object sender, RoutedEventArgs e)
        {
            NewChoroba nce = new NewChoroba(grdChoroby.SelectedItem as Choroby);

            nce.Activate();
            nce.ShowDialog();
        }
        private void btnNowaChoroba_Click(object sender, RoutedEventArgs e)
        {
            NewChoroba nc = new NewChoroba();

            nc.Activate();
            bool?result = nc.ShowDialog();

            if (result == true)
            {
                populateChorobyGrid();
            }
        }