Find and get list of controls on page

If you want to find list of controls on Page you can use this method:

private List<T> GetControls<T>() where T:Control
{
 List<T> list = new List<T>();        
 foreach (Control rootControl in Controls)
 {
    foreach (Control control in rootControl.Controls)
    {
        if (control as T != null)
        {
            list.Add(control as T);
        }
    }
 }
 return list;
}

And a using is very simple. In example you can see how to change background to all labels:

List<Label> list = 
        GetControls<Label>();
list.ForEach(
    delegate (Label lab)
   {
     lab.BackColor = 
       System.Drawing.Color.Pink;
   }
);