private void button1_Click(object sender, EventArgs e)
{
frm_QuanLyTuyen frmqlt = new frm_QuanLyTuyen();
frmqlt.Show();
}
public frm_QLTramXe(frm_QuanLyTuyen frm)
{
InitializeComponent();
txtMaTram.ReadOnly = true;
frmMain = frm;
}