WinForm 窗体之间相互嵌套

public FrmScan()
{
            InitializeComponent();
            Form1 frm = new Form1();
            frm.Dock = DockStyle.Fill;
            frm.FormBorderStyle = FormBorderStyle.None;
            frm.TopLevel = false;
            this.Controls.Clear();
            this.Controls.Add(frm);
            frm.Show();
}