How can i select an autoincremented identity column whose value have to be used in another table.

hai..
For example i have 2 tables person1,data the id of person1 is set as autoincremented and there is another column named description when description is added to table desc id should be inserted to the second table data.whose value is same as id in person1.can u please help me...Here am attaching the code..
Thanks in advance..

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=book;User ID=sa;Password=nest123@!");
            con.Open();


            string query = "insert into person1(description) values('" + textBox3.Text + "')";
            
            SqlCommand cmd = new SqlCommand(query, con);
            cmd.ExecuteNonQuery();

            try
            {
                SqlCommand cm = new SqlCommand("select Id from person1 where description='" + textBox3.Text + "'",con);
                SqlDataReader rd = cm.ExecuteReader();

                while (rd.Read())
                {
                    string str = rd["Id"].ToString();

                }
                SqlCommand cmd2 = new SqlCommand("insert into data (name,age,desc_id) values('" + textBox1.Text + "','" + textBox2.Text + "','+str+')");
            }

            catch (SqlException ex)
            {
            }
        }
        
    }
}

Tags: C#, WPF