遍历页面上所有TextBox控件并给它赋值为string.Empty

编程遍历页面上所有TextBox控件并给它赋值为string.Empty?

void afunc (ControlCollection cc)
     {
         for (int i = 0; i < cc.Count; i++)
         {
             if (cc[i].GetType() == typeof(TextBox))
             {
                 ((TextBox)cc[i]).Text = string.Empty;
             }
             if (cc[i].HasControls())
             {
                 afunc(cc[i].Controls);
             }
         }
}
调用afunc(this.Page.Controls);
或
我在页面加了三个TextBox,用下面的语句输出:
foreach (Control c in Page.Controls)
{
    if c.GetType()==typeof(TextBox)
{
   TextBox tb = (TextBox) c;
....
}
}