private void back_button_Click(object sender, EventArgs e)
{
csv.error();
this.Close();
next_form = new System.Threading.Thread(open);
next_form.SetApartmentState(System.Threading.ApartmentState.STA);
next_form.Start();
}
private void Close_program_Click(object sender, EventArgs e)
{
csv.error();
this.Close();
}