private void btnWholeseler_Click(object sender, EventArgs e)
{
if (wh == null)
{
wh = new Wholesaler();
wh.MdiParent = this;
wh.FormClosed += new FormClosedEventHandler(wh_FormClosed);
wh.Show();
}
else
{
wh.Activate();
}
}
void wh_FormClosed(object sender, FormClosedEventArgs e)
{
wh = null;
}