请编程遍历页面上所有TextBox控件并给它赋值为空

private void InitialControl(ControlCollection objControlCollection)
    {
        foreach (Control objControl in objControlCollection)
        {
            if (objControl.HasControls())
            {
                InitialControl(objControl.Controls);
            }
            else
            {
                  TextBox textBox = objControl as TextBox;
                    if (textBox != null)
                    {
                        textBox.Text = "xx";
                    }

            }
        }
    }