private void button6_Click(object sender, EventArgs e)
{
checkBox2.Checked = false;
checkBox3.Checked = false;
checkBox4.Checked = false;
checkBox5.Checked = false;
checkBox6.Checked = false;
checkBox7.Checked = false;
checkBox8.Checked = false;
checkBox9.Checked = false;
checkBox10.Checked = false;
checkBox11.Checked = false;
checkBox12.Checked = false;
checkBox13.Checked = false;
checkBox14.Checked = false;
checkBox15.Checked = false;
rw_txt_price1.Text = "";
rw_txt_price2.Text = "";
rw_txt_dq.SelectedIndex = -1;
}