private void ckbChuaTra_CheckedChanged(object sender, EventArgs e)
        {
            txtPage.Text = "1";

            PhieuMuonDAO pm = new PhieuMuonDAO();

            if (ckhQuaHan.Checked == false)
            {
                listTK.DataSource = pm.GetListPhieuMuonbyPage(1, 0);
            }
            else if (ckhQuaHan.Checked == true)
            {
                listTK.DataSource = pm.GetListPhieuMuonbyPage(1, 1);
            }
        }
        private void txtPage_TextChanged(object sender, EventArgs e)
        {
            PhieuMuonDAO pm = new PhieuMuonDAO();

            if (ckhQuaHan.Checked == false)
            {
                PhanTrang();
                int nowPage = int.Parse(txtPage.Text);
                listTK.DataSource = pm.GetListPhieuMuonbyPage(nowPage, 0);
            }
            else if (ckhQuaHan.Checked == true)
            {
                PhanTrang();
                int nowPage = int.Parse(txtPage.Text);
                listTK.DataSource = pm.GetListPhieuMuonbyPage(nowPage, 1);
            }
        }
        void showTkMuonAll()
        {
            PhieuMuonDAO pm = new PhieuMuonDAO();

            listTK.DataSource = pm.GetListPhieuMuonbyPage(1, 0);
            string   query        = "Select count(*) from PhieuMuon Where TrangThaiTong=0";
            DateTime dt           = DateTime.Now;
            string   query1       = "Select count(*) from PhieuMuon Where TrangThaiTong=0 and NgayTra < '" + dt.ToString() + "'";
            int      sodongquahan = pm.GetSoLuong(query1);
            int      sodong       = pm.GetSoLuong(query);

            thanhtrangthai.Items[0].Text += sodong.ToString();
            thanhtrangthai.Items[1].Text += sodongquahan.ToString();

            foreach (DataGridViewRow row in dgvThongKe.Rows)
            {
                if (row.Cells[7].Value.ToString() == "Quá hạn")
                {
                    row.DefaultCellStyle.BackColor = Color.Red;
                }
            }
        }