private void Button_Click_Update(object sender, RoutedEventArgs e)
        {
            if (flag2)
            {
                if (flag_ch)
                {
                    this.Weight.Visibility     = Visibility.Hidden;
                    this.Add_weight.Visibility = Visibility.Visible;
                    this.Button_update.Content = "Сохранить";
                    flag2 = false;
                }
                else
                {
                    var win_er = new ERRORWin();
                    win_er.ChooseError("ERRORNotTrain");
                    win_er.Show();
                }
            }
            else
            {
                this.Weight.Visibility     = Visibility.Visible;
                this.Add_weight.Visibility = Visibility.Hidden;
                Regex           reg     = new Regex(@"^[0-9]*[,]?[0-9]+$");
                MatchCollection matches = reg.Matches(this.Add_weight.Text);
                if (matches.Count > 0)
                {
                    this.Weight.Text           = this.Add_weight.Text;
                    this.Button_update.Content = "Обновить";

                    flag2 = true;

                    using (StaticsticContext db = new StaticsticContext())
                    {
                        db.Staticstics.Load();
                        var list = db.Staticstics.Local.ToBindingList();
                        int key  = 0;
                        foreach (var item in list)
                        {
                            if (item.ID_user == user.ID_user)
                            {
                                key = item.ID_session;
                            }
                        }
                        if (key != 0)
                        {
                            var item = db.Staticstics.Find(key);
                            if (item != null)
                            {
                                item.Weight_note = this.Add_weight.Text;
                                db.SaveChanges();
                            }
                        }
                    }
                    this.Add_weight.Text = "00,0";
                    var win_stat = new Statistics_train(user);
                    this.Main_Frame.Navigate(win_stat);
                }
                else
                {
                    this.Button_update.Content = "Обновить";
                    this.Add_weight.Text       = "00,0";
                    flag2 = true;
                    var win_a = new ERRORWin();
                    win_a.ChooseError("ERRORDataEntry");
                    win_a.Show();
                }
            }
        }
        private void Button_Click_Open_statistics(object sender, RoutedEventArgs e)
        {
            var win_stat = new Statistics_train(user);

            this.Main_Frame.Navigate(win_stat);
        }