清空文本框

   /// <summary>
    /// 清空页面文本框
    /// </summary>
    private void cleartxtbox()
    {
        foreach (Control outerControl in this.Controls)
        {
            foreach (Control ctr in outerControl.Controls)
                if (ctr is TextBox)
                {
                    (ctr as TextBox).Text = String.Empty;
                }
        }
    }