void dat_FormClosed(object sender, FormClosedEventArgs e)
{
dat = null;
}
private void deleteATrainingInformationToolStripMenuItem_Click(object sender, EventArgs e)
{
if (dat== null)
{
dat = new DeleteATraining(n);
dat.MdiParent = this;
dat.FormClosed += dat_FormClosed;
dat.Show();
}
else
{
dat.Activate();
}
}
