baglanti.Open();
SqlCommand komut = new SqlCommand("insert into musteri(tc,adsoyad,telefon,adres,email) values((@tc,@adsoyad,@telefon,@adres,@email)", baglanti);
komut.Parameters.AddWithValue("@tc", txtTc.Text);
komut.Parameters.AddWithValue("@adsoyad", txtAdSoyad.Text)...