private void btnThemMoi_Click(object sender, EventArgs e)
        {
            KhoanChi_Session.themhoacsua = 1; // là đang thêm
            frmThemhoacsuaKC kc = new frmThemhoacsuaKC();

            kc.ShowDialog();
            string thoigian = DateTime.Now.ToString("yyyy-MM");

            LoadData(thoigian);
        }
        private void btnSua_Click(object sender, EventArgs e)
        {
            KhoanChi_Session.themhoacsua = 2;
            int makc = Convert.ToInt32(gridView1.GetRowCellValue(gridView1.FocusedRowHandle, "makc").ToString());

            KhoanChi_Session.makc = makc;
            frmThemhoacsuaKC kc = new frmThemhoacsuaKC();

            kc.ShowDialog();
            string thoigian = dtpThoiGianXem.Text;

            LoadData(thoigian);
        }