private void btn_DangKi_Click(object sender, EventArgs e)
{
frmDangKi dk = new frmDangKi();
panel_Show.Show();
panel_Show.Controls.Clear();
dk.TopLevel = false;
dk.Dock = DockStyle.Fill;
panel_Show.Controls.Add(dk);
dk.Show();
}
private void btnDangKi_Click(object sender, EventArgs e)
{
frmDangKi f = new frmDangKi();
f.ShowDialog();
}