//C#
private void SetTextBoxBackColor(Control Page, Color clr)
{
     foreach (Control ctrl in Page.Controls)
     {
          if (ctrl is TextBox)
          {
              ((TextBox)(ctrl)).BackColor = clr;
          }
          else 
          {
              if (ctrl.Controls.Count > 0)
              {
                   SetTextBoxBackColor(ctrl, clr);
              }
          }
     }
}

//遍历form中的控件查找哪个RadioButton是否被选中
            foreach (Control control in this.form.Controls)
            {
                if (control is RadioButton)
                {
                    //如果Checked
                    if ((control as RadioButton).Checked == true)
                    {
                       //TODO
                    }
                }
            }