private void mnuBanHang_Click(object sender, EventArgs e) { frm_BanHang frmBanHang = frm_BanHang.Instance; frmBanHang.MdiParent = this; frmBanHang.Dock = DockStyle.Fill; frmBanHang.Show(); }
private void frm_BanHang_FormClosed(object sender, FormClosedEventArgs e) { _Instance = null; }