private void button7_Click(object sender, EventArgs e)
        {
            FormNhapHang FNH = new FormNhapHang();

            FNH.Show();
            this.Hide();
        }
 private void btnQuayLai_Click(object sender, EventArgs e)
 {
     if (FormNhapHang.MoFormTTNCC.MoFormNCC == 1)
     {
         FormNhapHang.MoFormTTNCC.MoFormNCC = 0;
         FormNhapHang FNH = new FormNhapHang();
         FNH.Show();
         this.Close();
     }
     else if (FormNhapHang.MoFormTTNCC.MoFormNCC != 1)
     {
         FormTrangChu ftc = new FormTrangChu();
         ftc.Show();
         this.Close();
     }
 }