private void dataKasirToolStripMenuItem_Click(object sender, EventArgs e) { if (kasir == null) { kasir = new Kasir(); kasir.MdiParent = this; kasir.FormClosed += new FormClosedEventHandler(Kasir_Closed); kasir.Show(); } else { kasir.Activate(); } }
void Kasir_Closed(object sender, FormClosedEventArgs e) { kasir = null; }