private void laporanBukuToolStripMenuItem_Click(object sender, EventArgs e) { if (buku == null) { buku = new L_buku(); buku.MdiParent = this; buku.FormClosed += new FormClosedEventHandler(L_buku_Closed); buku.Show(); } else { buku.Activate(); } }
void L_buku_Closed(object sender, FormClosedEventArgs e) { buku = null; }