private void btnAdd_Click(object sender, EventArgs e)
{
AddList al = new AddList();
al.Show();
al.Owner = this;//重要的一步，主要是使Form2的Owner指針指向Form1
}
private void toolStripMenuItem3_Click(object sender, EventArgs e)
{
AddList add_list = new AddList();
add_list.Show();
add_list.Owner = this;
}