WPF textbox 鼠标滚动更新日期，text文本值更改

　　 　　 /// <summary>
        /// 选择日期
        /// </summary>
        private void RQTxt_MouseWheel(object sender, MouseWheelEventArgs e)
        {
            if (XZQTxt.IsSelectionActive && XZQTxt.Text != null)
                Math(e.Delta, XZQTxt);
        }

        /// <summary>
        /// 输入月份更新文本
        /// </summary>
        /// <param name="e">滚轮上翻（正）还是下翻（负）</param>
        /// <param name="text">事件发生前的文本值</param>
        public void Math(int e, TextBox time)
        {
            string text = time.Text;
            ShowTXT(time, e, text, text.Substring(, ), "", "");
            switch (text.Substring(, ))
            {
                case "":
                    ShowTXT(time, e, text, "", "", "");
                    break;
                case "":
                    ShowTXT(time, e, text, "", "", "");
                    break;
                case "":
                    ShowTXT(time, e, text, "", "", "");
                    break;
                case "":
                    ShowTXT(time, e, text, "", "", "");
                    break;
                case "":
                    ShowTXT(time, e, text, "", "", "");
                    break;
                default:
                    break;
            }
        }

        /// <summary>
        /// 显示文本
        /// </summary>
        /// <param name="e">滚轮上翻（正）还是下翻（负）</param>
        /// <param name="text">事件发生前的文本值</param>
        /// <param name="YF">月份</param>
        /// <param name="ZYS">这月的天数</param>
        /// <param name="SYS">上月的天数</param>
        public void ShowTXT(TextBox time, int e, string text, string YF, string ZYS, string SYS)
        {
            if (Convert.ToInt32(text.Substring(, )) + (e / ) > Convert.ToInt32(ZYS) && e > )
                time.Text = text.Substring(, ) + "" + (Convert.ToInt32(YF.Substring()) + ) + "";
            else if ((Convert.ToInt32(text) + (e / )).ToString().Substring(, ) == "" && e < )
                time.Text = text.Substring(, ) + "" + (Convert.ToInt32(YF.Substring()) - ) + SYS;
            else
                time.Text = (Convert.ToInt32(text) + e / ).ToString();
        }