private void LogOut_buttonItem18_Click(object sender, EventArgs e)
        {
            CloseAllTab();
            hideMenu();
            LogOut_buttonItem18.Enabled = false;
            LogInbuttonItem17.Enabled   = true;
            frmDangN frm = new frmDangN(this);

            frm.ShowDialog();
        }
        private void buttonItem3_Click(object sender, EventArgs e)
        {
            CloseAllTab();
            hideMenu();
            QLD_ribbonBar9.Enabled = false;
            BcDiemThiSinhVien_ribbonBar12.Enabled = false;
            CapNhatTK_ribbonBar1.Visible          = false;

            frmDangN frm = new frmDangN(this);

            frm.ShowDialog();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            //  LogIn_ribbonBar1.Visible = false;
            hideMenu();
            QLD_ribbonBar9.Enabled = false;
            BcDiemThiSinhVien_ribbonBar12.Enabled = false;
            BcTKGiangVien_ribbonBar14.Visible     = false;
            CapNhatTK_ribbonBar1.Visible          = false;
            frmDangN _frmLog = new frmDangN(this);

            _frmLog.ShowDialog();
            this.reportViewer1.RefreshReport();
        }
        private void buttonItem2_Click(object sender, EventArgs e)
        {
            frmDangN _frmLog = new frmDangN(this);

            _frmLog.Show();
        }