BringToFront and SendToBack MDI Controls in C#

Question

Sir, I am using a MDI form in C#.

I need your help to bring the controls Front when I close a parent form.

 I did the code to send the controls to back when I open a parent form.

here is the code :-


 if (MdiChildren != null)
            {
                btnaddProduct.SendToBack();
                btnpurchaseDetails.SendToBack();
                btnRegister.SendToBack();

            }

 
here is the form before open a mdichild form





and the MDI form when open a child form





I want the code to send these controls ToBack and ToFront when ever I open and close a form