private void btnThoat_Click(object sender, EventArgs e)
{
DangNhapForm dlg = new DangNhapForm();
dlg.Show();
this.Close();
}
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
DangNhapForm form = new DangNhapForm();
if (form.ShowDialog() == DialogResult.OK)
{
Application.Run(new MainForm());
}
}