System.Windows.Forms.Form.Show C# (CSharp) Method

		public void Show (IWin32Window owner)
		{
			if (owner == null)
				this.Owner = null;
			else
				this.Owner = Control.FromHandle (owner.Handle).TopLevelControl as Form;

			if (owner == this)
				throw new InvalidOperationException ("The 'owner' cannot be the form being shown.");

			if (TopLevelControl != this) {
				throw new InvalidOperationException ("Forms that are not top level"
					+ " forms cannot be displayed as a modal dialog. Remove the"
					+ " form from any parent form before calling Show.");
			}

			base.Show ();
		}

 protected override void OnKeyDown(KeyEventArgs e)
 {
     base.OnKeyDown(e);
     switch (e.KeyCode)
     {
         case Keys.D:
             if (form == null)
             {
                 form = new Form();
                 form.Text = "Undocked Control";
                 form.Width = Width;
                 form.Height = Height;
                 form.FormBorderStyle = FormBorderStyle.SizableToolWindow;
                 this.Controls.Remove(control);
                 form.Controls.Add(control);
                 form.FormClosed += delegate (object sender,FormClosedEventArgs ee)
                 {
                     form.Controls.Remove(control);
                     this.Controls.Add(control);
                     form = null;
                 };
                 form.Show();
             }
             else
             {
                 form.Close();
             }
             break;
     }
 }