private void btnEditPaper_Click(object sender, EventArgs e)
{
PaperIndex = listBoxPapers.SelectedIndex;
FormPaper fp = new FormPaper(this);
fp.ShowDialog();
}
private void btnAddPaper_Click(object sender, EventArgs e)
{
paperIndex = -1;
FormPaper fp = new FormPaper(this);
fp.ShowDialog();
}