private void DangKy_FormClosing(object sender, FormClosingEventArgs e)
{
DialogResult rs;
rs = MessageBox.Show("Bạn muốn thoát?", "Thông báo!", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1);
if (rs == DialogResult.Yes)
{
TrangChu tc = new TrangChu();
tc.Show();
this.Hide();
}
}