private void button1_Click(object sender, EventArgs e)
        {
            conn.Open();
            string sql = "insert into test values('" + richTextBox1.Rtf +"')";
            SqlCommand cmd = new SqlCommand(sql, conn);
            cmd.ExecuteNonQuery();
            cmd = new SqlCommand("select   *   from   test ", conn);
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                richTextBox2.Rtf = dr.GetValue(1).ToString();
            }
            dr.Close();
            conn.Close();
        }