1  
   2              //"Display" is the form name
   3              foreach (Form childForm in this.MdiChildren)
   4              {
   5                  if (childForm.GetType() == typeof(Display))
   6                  {
   7                      childForm.Focus();
   8                      return;
   9                  }
  10              }
  11              Display frmDisplay = new Display();
  12              frmDisplay.MdiParent = this;
  13              frmDisplay.Show();