子窗体在MDI主窗体中,不显示窗体头。

            Form1 childForm = new Form1();
            // 在显示该窗体前使其成为此 MDI 窗体的子窗体。
            childForm.MdiParent = this;

            childForm.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            childForm.ControlBox = false;
        
            childForm.Padding = new Padding(4, 3, 4, 4);
     
            childForm.Text = "";
            childForm.Show();
            childForm.WindowState = System.Windows.Forms.FormWindowState.Maximized;