private void manageToolStripMenuItem_Click(object sender, EventArgs e) { if (am == null) { am = new aboutManage(); am.MdiParent = this; am.FormClosed += am_FormClosed; am.Show(); } else { am.Activate(); } }
void am_FormClosed(object sender, FormClosedEventArgs e) { am = null; //throw new NotImplementedException(); }