private void btnMoBan_Click(object sender, EventArgs e)
{
btnMoBan.Visible = false;
btnDongBan.Visible = true;
btnThanhToan.Enabled = true;
bllBanHang.MoBan(maBan);
bllBanHang.InsertNewHoaDon(maBan, DateTime.Now, DateTime.Now);
lblMaHoaDon.Text = bllBanHang.GetMaHoaDonOfBan(maBan);
lblGioVao.Text = GetGioVao(lblMaHoaDon.Text);
//LoadChiTietHoaDon(lblMaHoaDon.Text);
fpnlBan.Controls.Clear();
LoadBan(cboViTri.SelectedValue.ToString());
lblTrangThai.Text = "Có khách";
}