public frmSuaKH(int id)
{
InitializeComponent();
idKH = id;
DataTable dt = KhachHangControl.layThongTin(id);
txtTenCu.Text = dt.Rows[0][1].ToString();
txtDiaChiCu.Text = dt.Rows[0][2].ToString();
txtSDTCu.Text = dt.Rows[0][3].ToString();
}