private void button2_Click(object sender, EventArgs e)
        {
            int         id  = (int)textBox2.Tag;
            Personeller sil = baglanti.PersonellerSet.SingleOrDefault(f => f.personel_id == id);

            baglanti.PersonellerSet.Remove(sil);
            baglanti.SaveChanges();
            dataGridView1.DataSource = baglanti.PersonellerSet.ToList();
            Temizle();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Personeller ekle = new Personeller();

            ekle.PersonelAdSoyad        = textBox2.Text;
            ekle.PersonelTel            = maskedTextBox1.Text;
            ekle.Departman_departman_id = Convert.ToInt32(comboBox1.SelectedValue);
            baglanti.PersonellerSet.Add(ekle);
            baglanti.SaveChanges();
            dataGridView1.DataSource = baglanti.PersonellerSet.ToList();
            Temizle();
        }
        private void button4_Click(object sender, EventArgs e)
        {
            int id = (int)textBox2.Tag;

            Personeller yenile = baglanti.PersonellerSet.SingleOrDefault(g => g.personel_id == id);

            yenile.PersonelAdSoyad        = textBox2.Text;
            yenile.PersonelTel            = maskedTextBox1.Text;
            yenile.Departman_departman_id = Convert.ToInt32(comboBox1.SelectedValue);
            baglanti.SaveChanges();
            dataGridView1.DataSource = baglanti.PersonellerSet.ToList();
            Temizle();
        }