Cast Control To WebControl

I am iterating through controls on a page and need to cast them to a webcontrol to access attribute property.

Can someone give me a quick example of how to cast a control to a web control?

        public void FetchControls(Control c)
        {
            try
            {
                WebControl wc = (WebControl)c;

                DistributeToSets(wc);

                // Run FetchControls again if the current control is a parent and has child controls.
                if (c.HasControls())
                {
                    foreach (Control cc in c.Controls)
                    {
                        FetchControls(cc);
                    }
                }
            }
            catch (Exception ex)
            {
                debug("Failed casting from Control to WebControl.");
                debug(ex.Message);
            }
        }

Executing this gives me an invalid cast exception for ALL the controls.

Any tips will be appreciated!