private void ThemTram(object sender, EventArgs e)
        {
            FormTram frm = new FormTram();

            frm.txtIDTram.Text = MaTramTuTang();
            frm.Show();
        }
        private void btnSua_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(IDDangChon))
            {
                MessageBox.Show("Click Vào Dòng Muốn Sửa");
                return;
            }
            FormTram frm5 = new FormTram();

            frm5.txtIDTram.Text    = IDDangChon;
            frm5.txtIDTram.Enabled = false;
            frm5.Show();

            LoadQLTram();
        }