private void dataBarangToolStripMenuItem_Click(object sender, EventArgs e)
 {
     //10.
     if (brg == null)
     {
         brg             = new GUI.FBarang();
         brg.MdiParent   = this;
         brg.FormClosed += new FormClosedEventHandler(Proc_BarangClosed);
         brg.Show();
     }
     else
     {
         brg.Activate();
     }
 }
 //7.
 void Proc_BarangClosed(Object sender, FormClosedEventArgs e)
 {
     brg = null;
 }