private void button1_Click(object sender, EventArgs e)
        {
            var client = context.Clients.FirstOrDefault(c => c.EGN == textBox1.Text);

            if (client != null && comboBox2.Text != string.Empty)
            {
                bool isAdd = insert.InsertIntoReservation(textBox1.Text, comboBox1.Text, dateTimePicker1.Value.Date, dateTimePicker2.Value.Date, decimal.Parse(comboBox2.Text), textBox3.Text);
                if (isAdd)
                {
                    context.Rooms.FirstOrDefault(r => r.RoomNumebr == comboBox1.Text).isFree = false;
                    context.SaveChanges();
                    comboBox1.Items.Clear();
                    LoadFreeRooms();
                    MessageBox.Show("Добавен");
                }
                else
                {
                    MessageBox.Show("Не");
                }
            }
            else
            {
                AddClients settingsForm = new AddClients(context);
                settingsForm.Show();
            }
        }
        private void button3_Click(object sender, EventArgs e)
        {
            AddClients form = new AddClients(context);

            form.Show();
        }