private async void Button3_Click(object sender, EventArgs e)
        {
            Package selectedPackage = (Package)comboBox1.SelectedItem;

            selectedPackage.Name = textBox1.Text.Trim();
            Time selectedTime = (Time)comboBox2.SelectedItem;

            selectedPackage.Time = selectedTime;
            selectedPackage.Price__per_month_ = numericPrice.Value;

            foreach (var item in fitnessEntities.ServicesToPackages.Where(stp => stp.PackageId == selectedPackage.id).ToList())
            {
                fitnessEntities.ServicesToPackages.Remove(item);
            }
            await fitnessEntities.SaveChangesAsync();

            foreach (var item in flowLayoutPanel1.Controls)
            {
                CheckBox checkbox = (CheckBox)item;
                if (checkbox.Checked)
                {
                    ServicesToPackage servicesToPackage = new ServicesToPackage();
                    servicesToPackage.PackageId = selectedPackage.id;
                    servicesToPackage.ServiceId = (int)checkbox.Tag;
                    fitnessEntities.ServicesToPackages.Add(servicesToPackage);
                }
            }
            await fitnessEntities.SaveChangesAsync();

            MessageBox.Show("Seçilmiş paketin məlumatları yeniləndi");
            textBox1.Text = "";
            comboBox1.Items.Clear();
            comboBox1.Items.AddRange(fitnessEntities.Packages.ToArray());
            comboBox2.SelectedIndex = -1;
            numericPrice.Value      = 0;
            foreach (var item in flowLayoutPanel1.Controls)
            {
                CheckBox checkbox = (CheckBox)item;
                checkbox.Checked = false;
            }
        }
        private async void Button1_Click(object sender, EventArgs e)
        {
            string  name    = textBox1.Text.Trim();
            Time    time    = (Time)comboBox2.SelectedItem;
            decimal price   = numericPrice.Value;
            Package package = new Package();

            package.Name = name;
            package.Time = time;
            package.Price__per_month_ = price;
            fitnessEntities.Packages.Add(package);
            await fitnessEntities.SaveChangesAsync();

            foreach (var item in flowLayoutPanel1.Controls)
            {
                CheckBox checkbox = (CheckBox)item;
                if (checkbox.Checked)
                {
                    ServicesToPackage servicesToPackage = new ServicesToPackage();
                    servicesToPackage.ServiceId = Convert.ToInt32(checkbox.Tag);
                    servicesToPackage.PackageId = package.id;
                    fitnessEntities.ServicesToPackages.Add(servicesToPackage);
                }
            }
            await fitnessEntities.SaveChangesAsync();

            MessageBox.Show("Yeni paket əlavə olundu");
            textBox1.Text = "";
            comboBox1.Items.Clear();
            comboBox1.Items.AddRange(fitnessEntities.Packages.ToArray());
            comboBox2.SelectedIndex = -1;
            numericPrice.Value      = 0;
            foreach (var item in flowLayoutPanel1.Controls)
            {
                CheckBox checkbox = (CheckBox)item;
                checkbox.Checked = false;
            }
        }