DDWiki/实践/后端/C#基础/19.C#中关于时间.md

关于年的问题

• DownList显示年，可根据当前的年份，具体代码 public List<string> GetYears() { List<string> allYears = new List<string>(); var now = DateTime.Now; int currentYear = now.Year;//2019 allYears.Add((currentYear - 3).ToString());//2016 allYears.Add((currentYear - 2).ToString());//2017 allYears.Add((currentYear - 1).ToString());//2018 allYears.Add(currentYear.ToString());//2019 allYears.Add((currentYear + 1).ToString());//2020 allYears.Add((currentYear + 2).ToString());//2021 allYears.Add((currentYear + 3).ToString());//2022 return allYears; }

关于月的问题

• DownList显示月。因为月是具体的24个月，可直接增添值 public List<string> GetMonths() { List<string> allMonths = new List<string>(); allMonths.AddRange(new List<string> { "01","02","03","04","05","06","07","08","09","10","11","12"}); return allMonths; }

关于天的问题

• 因为每年的每个月的天数不确定，可以根据请求或者选择的年月进行显示天数

  /// <summary>
      /// 获取天
      /// </summary>
      /// <param name="year"></param>
      /// <param name="month"></param>
      /// <returns></returns>
      public List<string> GetDays(string year, string month)
      {
          var result = new List<string>();
  
          if(!string.IsNullOrEmpty(year) && !string.IsNullOrEmpty(month))
          {
              //拼接月和年 2019-04
              string yearAndMonthStr = year + "-" + month;
              //月初 2019-04-01
              DateTime beginTime = DateTime.Parse(yearAndMonthStr + "-01");
              DateTime endTime = DateTime.Parse(beginTime.AddMonths(1).AddDays(-1).ToShortDateString());
              //月末
              for (DateTime dt = beginTime; dt <= endTime; dt = dt.AddDays(1))
              {
                  result.Add(dt.Day.ToString());
              }
          }
              
          return result;
      }
  

  时间格式转换（12或者24小时） ``` string time = Convert.ToDateTime(date).ToString(“yyyy-MM-dd HH:mm”);//HH为24小时 string time = Convert.ToDateTime(date).ToString(“yyyy-MM-dd hh:mm”);//hh为12小时

```