利用Control类的Controls可取得子控件集合，依据Controls.Count获得的子控件数目，用Control.Controls[n].属性名 访问相关属性

  private void ResetTextBox(System.Windows.Forms.Control.ControlCollection cc, Boolean boolean)
        {

            // 利用Control类的Controls可取得子控件集合

            foreach (Control ctr in cc)
            {

                if (ctr is TextBox)
                {

                    string ctrName = ctr.Name;
                    ctrName = ctrName.Substring(ctrName.Length - 1);
                   
                    int i = int.Parse(ctrName);

                    if (i > 0 && i <= 9) { ((TextBox)ctr).ReadOnly = boolean; }

                }
            }
        }

调用时:ResetTextBox(this.Controls);