C# SQL server veri tabanı Update sorunu

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;
using System.Data.Sql;

namespace StokTakipOtomasyonu
{
    public partial class FrmMusteriListelemecs : Form
    {
        public FrmMusteriListelemecs()
        {
            InitializeComponent();
        }
        SqlConnection baglanti = new SqlConnection("Data Source=DESKTOP-9IIMV9N\\SQLEXPRESS;Initial Catalog=StokTakipUyg;Integrated Security=True");
        DataSet daset = new DataSet();

        private void FrmMusteriListelemecs_Load(object sender, EventArgs e)
        {
            kayit_goster();
        }

        private void kayit_goster()
        {
            baglanti.Open();
            SqlDataAdapter adtr = new SqlDataAdapter("select *from musteribilgi", baglanti);
            adtr.Fill(daset, "musteribilgi");
            dataGridView1.DataSource = daset.Tables["musteribilgi"];
            baglanti.Close();
        }

        private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
            txtTc.Text = dataGridView1.CurrentRow.Cells["tc"].Value.ToString();
            txtAdSoyad.Text = dataGridView1.CurrentRow.Cells["adsoyad"].Value.ToString();
            txtTelefon.Text = dataGridView1.CurrentRow.Cells["telefon"].Value.ToString();
            txtAdres.Text = dataGridView1.CurrentRow.Cells["adres"].Value.ToString();
            txtEmail.Text = dataGridView1.CurrentRow.Cells["email"].Value.ToString();

        }

        private void txtTcAra_TextChanged(object sender, EventArgs e)
        {
            DataTable tablo = new DataTable();
            baglanti.Open();
            SqlDataAdapter adtr = new SqlDataAdapter("select *from musteribilgi where tc like '%" + txtTcAra.Text + "%'", baglanti);
            adtr.Fill(tablo);
            dataGridView1.DataSource = tablo;
            baglanti.Close();
        }

        private void btnSil_Click(object sender, EventArgs e)
        {
            baglanti.Open();
            SqlCommand komut = new SqlCommand("delete from musteribilgi where tc='" + dataGridView1.CurrentRow.Cells["tc"].Value.ToString() + "'", baglanti);
            komut.ExecuteNonQuery();
            baglanti.Close();
            daset.Tables["musteribilgi"].Clear();
            kayit_goster();
            MessageBox.Show("Kayıt silindi");
        }

        private void btnGuncelle_Click(object sender, EventArgs e)
        {
            baglanti.Open();
            SqlCommand komut = new SqlCommand("update musteribilgi set adsoyad=@adsoyad,telefon=@telefon,adres=@adres,email=@email where tc=@tc", baglanti);
            komut.Parameters.AddWithValue("@adsoyad", txtAdSoyad.Text);
            komut.Parameters.AddWithValue("@telefon", txtTelefon.Text);
            komut.Parameters.AddWithValue("@adres", txtAdres.Text);
            komut.Parameters.AddWithValue("@email", txtEmail.Text);
            komut.Parameters.AddWithValue("@tc", txtTc.Text);
            komut.ExecuteNonQuery();
            baglanti.Close();
            daset.Tables["musteribilgi"].Clear();
            kayit_goster();
            MessageBox.Show("Müşteri kaydı güncellendi");
            foreach (Control item in groupBox1.Controls)
            {
                if (item is TextBox)
                {
                    item.Text = "";
                }
            }
        }
    }
}

SqlCommand komut = new SqlCommand("update musteribilgi set adsoyad=@adsoyad,telefon=@telefon,adres=@adres,email=@email where tc="+txtTc.Text, baglanti);

SqlCommand komut = new SqlCommand("update musteribilgi set adsoyad=@adsoyad,telefon=@telefon,adres=@adres,email=@email where tc="+Convert.ToInt32(txtTc.Text), baglanti);