Using ControlCollection class to create an "EditMode" feature

Hello. 
 I'm trying to create an "EditMode" feature by adding Controls to a ControlCollection class and "toogling" their Visible property. 



However, the controls are not been show in the page even when their Visible property is TRUE. I am guessing when I use the first 3 lines of code something wrong happens to them, but I'm not quite sure what it is.
 Can anyone help?
 
Tks!

ControlCollection EditModeControls = new ControlCollection(this);
EditModeControls.Add(ctl1);
EditModeControls.Add(ctl2);

foreach (Control c in EditModeControls)
{

if (c.Visible == true)
c.Visible = true;
...