private void Button_Click_Delete_Row(object sender, RoutedEventArgs e) { int id = (FriendsDataGrid.SelectedItem as user).user_id; FriendService friendService = new FriendService(); using (SteamContext context = new SteamContext()) { user tmp = (from user in context.Users where user.user_id == id select user).SingleOrDefault(); friendService.DeleteFriends(tmp); } user user2 = new user() { user_id = 2, nickname = "EEE", register_date = new DateTime(1582, 10, 5), status_id = 1, IsDeleted = 0, password = "******", wallet_id = 1 }; var userFriends = friendService.GetUserFriends(user2); FriendsDataGrid.ItemsSource = userFriends; }