日期操作常用代码

using System;

namespace My.Utils {
/// <summary>
/// 日期操作常用工具
/// </summary>
public class DateUtils {
   public DateUtils() {
   }

         /// <summary>
         /// 比较日期的年份差
         /// </summary>
         /// <param name="start">开始日期</param>
         /// <returns>与当前日期的年份差</returns>
         public static int DiffYear (string start) {
             return DiffYear(Convert.ToDateTime(start));
         }

         /// <summary>
         /// 比较日期的年份差
         /// </summary>
         /// <param name="start">开始日期</param>
         /// <param name="end">结束日期</param>
         /// <returns>年份差</returns>
         public static int DiffYear (string start, string end) {
             return DiffYear(Convert.ToDateTime(start), Convert.ToDateTime(end));
         }
        
         /// <summary>
         /// 比较日期的年份差
         /// </summary>
         /// <param name="start">开始日期</param>
         /// <returns>与当前日期的年份差</returns>
         public static int DiffYear (DateTime start) {
             return (DiffYear(start, DateTime.Now));
         }

         /// <summary>
         /// 比较两个日期的年份差
         /// </summary>
         /// <param name="start">开始日期</param>
         /// <param name="end">结束日期</param>
         /// <returns>年份差</returns>
         public static int DiffYear (DateTime start, DateTime end) {
             return (end.Year - start.Year);
         }

         /// <summary>
         /// 格式化当天日期(yyyy-MM-dd)
         /// </summary>
         /// <returns>格式化后的日期字符串</returns>
         public static string DateFormat () {
             return DateFormat(DateTime.Now);
         }

         /// <summary>
         /// 格式化日期(yyyy-MM-dd)
         /// </summary>
         /// <param name="date">待格式化的日期</param>
         /// <returns>格式化后的日期字符串</returns>
         public static string DateFormat (string date) {
             return DateFormat(Convert.ToDateTime(date));
         }

         /// <summary>
         /// 格式化日期
         /// </summary>
         /// <param name="date">待格式化的日期</param>
         /// <param name="format">格式化串</param>
         /// <returns>格式化后的日期字符串</returns>
         public static string DateFormat (string date, string format) {
             return DateFormat(Convert.ToDateTime(date), format);
         }

         /// <summary>
         /// 格式化日期(yyyy-MM-dd)
         /// </summary>
         /// <param name="date">待格式化的日期</param>
         /// <returns>格式化后的日期字符串</returns>
         public static string DateFormat (DateTime date) {
             return DateFormat(date, "yyyy-MM-dd");
         }

         /// <summary>
         /// 格式化日期
         /// </summary>
         /// <param name="date">待格式化的日期</param>
         /// <param name="format">格式化串</param>
         /// <returns>格式化后的日期字符串</returns>
         public static string DateFormat (DateTime date, string format) {
             return date.ToString(format);
         }

         /// <summary>
         /// 格式化日期时间
         /// </summary>
         /// <param name="datetime">待格式化的日期时间</param>
         /// <returns>格式化后的日期时间字符串</returns>
         public static string DateTimeFormat (DateTime datetime) {
             return DateTimeFormat(datetime, "yyyy-MM-dd HH:mm");
         }

         /// <summary>
         /// 格式化日期时间
         /// </summary>
         /// <param name="datetime">待格式化的日期时间</param>
         /// <param name="format">格式化串</param>
         /// <returns>格式化后的日期时间字符串</returns>
         public static string DateTimeFormat (DateTime datetime, string format) {
             return datetime.ToString(format);
         }
}
}