protected void btn1_Click(object sender, EventArgs e)
    {
        List<string> selected = CheckBoxList1.Items.Cast<ListItem>()
            .Where(li => li.Selected)
            .Select(li => li.Value)
            .ToList();

        using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
        {

            foreach (string item in selected)
            {

                String sqlUpdate = "insert into OficinasHasServicos values (8, @idservico)";

                SqlCommand command = new SqlCommand(sqlUpdate, con);
                command.Parameters.AddWithValue("@idservico", item.ToString());
                con.Open();
                command.ExecuteNonQuery();
                con.Close();

                lit1.Text += "added " + item.ToString() + "<br>";


        }


        }
    }