How to get GUID from a row

 private void button1_Click(object sender, EventArgs e)
        {
            // Insert GuiD in Database
            Guid c = Guid.NewGuid();
            textBox1.Text = c.ToString();
            SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;Integrated Security=True;User Instance=True");
            con.Open();

            SqlCommand comm = new SqlCommand("insert into users(id) values('"+c.ToString()+"')",con);
            comm.ExecuteNonQuery();
          

            //Show Inserted GUID in DataGridView

            SqlCommand comm2 = new SqlCommand("select * from users",con);
            SqlDataAdapter da  = new SqlDataAdapter(comm2);
            DataSet ds = new DataSet();
            da.Fill(ds,"v");
            dataGridView1.DataSource = ds.Tables[0];

            //Retrive the Guid In MessageBox

            SqlCommand comm3 = new SqlCommand("select * from users",con);
            SqlDataReader reader = comm3.ExecuteReader();

            while (reader.Read())
            {
                Guid x = (Guid)(reader["id"]);
                MessageBox.Show(x.ToString());
            }

        }