Find control by id in a UserControl structure

Find control by id in a UserControl structure

The situations (Not mike the douchebag) :
I have a multitudes of UserControls it inherit from one parent.
On the parent Page_Load, I want to find a specific control from the child
UserControl and add it an Attributes.
The problem is I never know the structure of the child UserControl.
I tried to use a recursive method to find the control by id :
public static Control FindControlRecursive(Control root, string id)
{
if (root.ID == id)
return root;
return root.Controls.Cast<Control>()
.Select(c => FindControlRecursive(c, id))
.FirstOrDefault(c => c != null);
}
And this is how I call it from the parent:
Page page = HttpContext.Current.Handler as Page;
var mycontrol = FindControlRecursive(page, "id_x");
if (mycontrol != null)
{
string test = "";
}
But I don't work. I am really not sure if this is a good way to achieve my
goal. Please, I want to know if you have any suggestions or better way to
do it. Your help will be highly appreciated.