private void btnDeleteUser_Click(object sender, RoutedEventArgs e) { if (!IsTrueDbConfig()) { MessageBox.Show("Need right db configuration on the first tab."); return; } if (SelectedUser == null) { MessageBox.Show("Please select the user to delete."); return; } User userToDelete = SelectedUser; DatabaseConfig config = DbConfig; new Task((Action)(() => { MsSqlDataProvider provider = new MsSqlDataProvider(); DragonflyEntities context = provider.Initizlize(config) as DragonflyEntities; try { provider.DeleteUser(userToDelete.Login); Dispatcher.Invoke((Action)(() => { LoadUsersRunner(config); })); } catch (Exception ex) { MessageBox.Show(ex.ToString()); } })).Start(); }