private void btnThemSach_Click(object sender, EventArgs e)
        {
            Forms.frmSach frmS = new Forms.frmSach();

            frmS.myEvent += frm_myEvent;

            frmS.ShowDialog();
        }
        private void btnChinhSua_Click(object sender, EventArgs e)
        {

            try
            {
                string _mas = grid_Sach.GetRowCellValue(grid_Sach.FocusedRowHandle, grid_Sach.Columns["MaSach"]).ToString();
                
                // Truyen cai MaTL vua lay dx...qua ben form NhapTheLoai.
                Forms.frmSach frmS = new Forms.frmSach(_mas);
                frmS.myEvent += frm_myEvent;
                txtTim.Text = "";
                frmS.ShowDialog();
            }
            catch
            {
                XtraMessageBox.Show("Bạn phải chọn dòng chứa dữ liệu", Text, MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }