private void btn_kh_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
frm_KhachHang kh = new frm_KhachHang();
panel1.Controls.Clear();
panel1.Controls.Add(kh);
}
private void btn_chuyen_Click(object sender, EventArgs e)
{
frm_KhachHang kh = new frm_KhachHang();
kh.Show();
}