C#'da iki adet combox arasındaki verileri alma ve veritabanına kaydetme işlemi nasıl yapılır?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace emocan
{
    public partial class Form2 : Form
    {
        string baglantiCumlesi = "server=.\\SQLEXPRESS; database=emocan; integrated security=SSPI";
        List<string> RezerveSaatler;
        public Form2()
        {
            InitializeComponent();
            this.comboBox1.DrawMode = DrawMode.OwnerDrawFixed;
            this.comboBox1.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.comboBox1_DrawItem);
            this.comboBox2.DrawMode = DrawMode.OwnerDrawFixed;
            this.comboBox2.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.comboBox2_DrawItem);


        }
        private void Form2_Load(object sender, EventArgs e)
        {
            RezerveSaatler = GetirRezerveSaatler();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            SaatKaydet();


          //  bool flag = false;
            //foreach (var i in comboBox2.Items)
            //{
            //    if (i.ToString() == t1)
            //        flag = true;
            //    if (flag)
            //    {
            //        if (!DahaOnceRezerveEdilmisMi(i.ToString()))
            //            SaatKaydet(i.ToString());
            //        else
            //        {
            //            MessageBox.Show("Bu saat daha önce rezerve edilmiş");
            //        }
            //    }
            //    if (i.ToString() == t2)
            //        flag = false;
            //}

        }

        Font myFont = new Font("Arial", 10, FontStyle.Underline | FontStyle.Regular);
        Font myFont2 = new Font("Arial", 10, FontStyle.Italic | FontStyle.Strikeout);

        private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)
        {
            string saat = comboBox1.Items[e.Index].ToString();
            if (RezerveSaatler.Contains(saat))
            {
                e.Graphics.DrawString(comboBox1.Items[e.Index].ToString(), myFont2, Brushes.LightSlateGray, e.Bounds);


            }
            else
            {
                e.DrawBackground();
                e.Graphics.DrawString(comboBox1.Items[e.Index].ToString(), myFont, Brushes.Black, e.Bounds);
                e.DrawFocusRectangle();
            }


        }
        private void comboBox2_DrawItem(object sender, DrawItemEventArgs e)
        {
            string saat = comboBox2.Items[e.Index].ToString();
            if (RezerveSaatler.Contains(saat))
            {
                e.Graphics.DrawString(comboBox2.Items[e.Index].ToString(), myFont2, Brushes.LightSlateGray, e.Bounds);


            }
            else
            {
                e.DrawBackground();
                e.Graphics.DrawString(comboBox2.Items[e.Index].ToString(), myFont, Brushes.Black, e.Bounds);
                e.DrawFocusRectangle();
            }


        }


        void SaatKaydet()
        {
            var t1 = comboBox1.SelectedItem.ToString();
            var t2 = comboBox2.SelectedItem.ToString();
            var saat = t1 + "-" + t2;
            SqlConnection baglanti = new SqlConnection(baglantiCumlesi);
            SqlCommand komut = new SqlCommand("Insert Into Rezerve (Saat,Tarih) Values (@prmSaat,@prmTarih)", baglanti);
            komut.Parameters.AddWithValue("@prmSaat", saat);
            komut.Parameters.AddWithValue("@prmTarih", dateTimePicker1.Value);
            baglanti.Open();
            komut.ExecuteNonQuery();
            baglanti.Close();
        }
        bool DahaOnceRezerveEdilmisMi(string saat)
        {
            SqlConnection baglanti = new SqlConnection(baglantiCumlesi);
            SqlCommand komut = new SqlCommand("Select count(*) from Rezerve Where Saat=@prmSaat", baglanti);
            komut.Parameters.AddWithValue("@prmSaat", saat);
            baglanti.Open();
            int sonuc = (int)komut.ExecuteScalar();
            baglanti.Close();
            if (sonuc == 0)
                return false;
            else
                return true;
        }

        List<string> GetirRezerveSaatler()
        {
            List<string> rezerveler = new List<string>();
            
            using (SqlConnection connection = new SqlConnection(baglantiCumlesi))
            {
                connection.Open();
                using (SqlCommand command = new SqlCommand("SELECT Saat from Rezerve Where Tarih=@prmTarih", connection))
                {
                    command.Parameters.AddWithValue("@prmTarih", dateTimePicker1.Value.Date);
                    string saatAraligi = (string)command.ExecuteScalar();
                    if (!string.IsNullOrEmpty(saatAraligi))
                    {
                        string[] saatAraligiArray = saatAraligi.Split('-');
                        var baslangicSaati = saatAraligiArray[0];
                        var bitisSaati = saatAraligiArray[1];
                        bool flag = false;
                        foreach (var i in comboBox1.Items)
                        {
                            if (i.ToString() == baslangicSaati)
                                flag = true;
                            if (flag)
                                rezerveler.Add(i.ToString());
                            if (i.ToString() == bitisSaati)
                                flag = false;
                        }
                    }
                }
            }
            return rezerveler;
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox1.SelectedIndex != -1)
            {
                if (RezerveSaatler.Contains(comboBox1.SelectedItem.ToString()))
                    comboBox1.SelectedIndex = -1;
            }


        }

        private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox2.SelectedIndex != -1)
            {
                if (RezerveSaatler.Contains(comboBox2.SelectedItem.ToString()))
                    comboBox2.SelectedIndex = -1;
            }

        }

        private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
        {
            RezerveSaatler = GetirRezerveSaatler();
        }






    }
}