private void bbiDangNhapLai_ItemClick(object sender, ItemClickEventArgs e) { nguoiDungDTO = new NguoiDungDTO(); this.bsiTenNguoiDung.Caption = ""; this.ribbon.Visible = false; xtraTabbedMdiManager.ClosePageButtonShowMode = ClosePageButtonShowMode.Default; var form = new fDangNhap(); form.LoginEvent += form_LoginEvent; form.thoatChuongTrinh += form_thoatChuongTrinh; form.MdiParent = this; form.Show(); }