如何通过asp.net实现功能强大的时间日期处理类？

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
namespace MSCL
{
 /// <summary>
 /// 时间日期处理类
 /// </summary>
 public class DateTimeHelper
 {
  #region 返回本年有多少天
  /// <summary>返回本年有多少天</summary>
  /// <param name="iYear">年份</param>
  /// <returns>本年的天数</returns>
  public static int GetDaysOfYear(int iYear)
  {
   int cnt = 0;
   if (IsRuYear(iYear))
   {
    //闰年多 1 天 即：2 月为 29 天
    cnt = 366;
   }
   else
   {
    //--非闰年少1天 即：2 月为 28 天
    cnt = 365;
   }
   return cnt;
  }
  #endregion
  #region 返回本年有多少天
  /// <summary>本年有多少天</summary>
  /// <param name="dt">日期</param>
  /// <returns>本天在当年的天数</returns>
  public static int GetDaysOfYear(DateTime idt)
  {
   int n;
   //取得传入参数的年份部分，用来判断是否是闰年
   n = idt.Year;
   if (IsRuYear(n))
   {
    //闰年多 1 天 即：2 月为 29 天
    return 366;
   }
   else
   {
    //--非闰年少1天 即：2 月为 28 天
    return 365;
   }
  }
  #endregion
  #region 返回本月有多少天
  /// <summary>本月有多少天</summary>
  /// <param name="iYear">年</param>
  /// <param name="Month">月</param>
  /// <returns>天数</returns>
  public static int GetDaysOfMonth(int iYear, int Month)
  {
   int days = 0;
   switch (Month)
   {
    case 1:
     days = 31;
     break;
    case 2:
     if (IsRuYear(iYear))
     {
      //闰年多 1 天 即：2 月为 29 天
      days = 29;
     }
     else
     {
      //--非闰年少1天 即：2 月为 28 天
      days = 28;
     }
     break;
    case 3:
     days = 31;
     break;
    case 4:
     days = 30;
     break;
    case 5:
     days = 31;
     break;
    case 6:
     days = 30;
     break;
    case 7:
     days = 31;
     break;
    case 8:
     days = 31;
     break;
    case 9:
     days = 30;
     break;
    case 10:
     days = 31;
     break;
    case 11:
     days = 30;
     break;
    case 12:
     days = 31;
     break;
   }
   return days;
  }
  #endregion
  #region 返回本月有多少天
  /// <summary>本月有多少天</summary>
  /// <param name="dt">日期</param>
  /// <returns>天数</returns>
  public static int GetDaysOfMonth(DateTime dt)
  {
   //--------------------------------//
   //--从dt中取得当前的年，月信息 --//
   //--------------------------------//
   int year, month, days = 0;
   year = dt.Year;
   month = dt.Month;
   //--利用年月信息，得到当前月的天数信息。
   switch (month)
   {
    case 1:
     days = 31;
     break;
    case 2:
     if (IsRuYear(year))
     {
      //闰年多 1 天 即：2 月为 29 天
      days = 29;
     }
     else
     {
      //--非闰年少1天 即：2 月为 28 天
      days = 28;
     }
     break;
    case 3:
     days = 31;
     break;
    case 4:
     days = 30;
     break;
    case 5:
     days = 31;
     break;
    case 6:
     days = 30;
     break;
    case 7:
     days = 31;
     break;
    case 8:
     days = 31;
     break;
    case 9:
     days = 30;
     break;
    case 10:
     days = 31;
     break;
    case 11:
     days = 30;
     break;
    case 12:
     days = 31;
     break;
   }
   return days;
  }
  #endregion
  #region 返回当前日期的星期名称
  /// <summary>返回当前日期的星期名称</summary>
  /// <param name="dt">日期</param>
  /// <returns>星期名称</returns>
  public static string GetWeekNameOfDay(DateTime idt)
  {
   string dt, week = "";
   dt = idt.DayOfWeek.ToString();
   switch (dt)
   {
    case "Mondy":
     week = "星期一";
     break;
    case "Tuesday":
     week = "星期二";
     break;
    case "Wednesday":
     week = "星期三";
     break;
    case "Thursday":
     week = "星期四";
     break;
    case "Friday":
     week = "星期五";
     break;
    case "Saturday":
     week = "星期六";
     break;
    case "Sunday":
     week = "星期日";
     break;
   }
   return week;
  }
  #endregion
  #region 返回当前日期的星期编号
  /// <summary>返回当前日期的星期编号</summary>
  /// <param name="dt">日期</param>
  /// <returns>星期数字编号</returns>
  public static string GetWeekNumberOfDay(DateTime idt)
  {
   string dt, week = "";
   dt = idt.DayOfWeek.ToString();
   switch (dt)
   {
    case "Mondy":
     week = "1";
     break;
    case "Tuesday":
     week = "2";
     break;
    case "Wednesday":
     week = "3";
     break;
    case "Thursday":
     week = "4";
     break;
    case "Friday":
     week = "5";
     break;
    case "Saturday":
     week = "6";
     break;
    case "Sunday":
     week = "7";
     break;
   }
   return week;
  }
  #endregion
  #region 判断当前日期所属的年份是否是闰年，私有函数
  /// <summary>判断当前日期所属的年份是否是闰年，私有函数</summary>
  /// <param name="dt">日期</param>
  /// <returns>是闰年：True ，不是闰年：False</returns>
  private static bool IsRuYear(DateTime idt)
  {
   //形式参数为日期类型
   //例如：2003-12-12
   int n;
   n = idt.Year;
   if ((n % 400 == 0) || (n % 4 == 0 && n % 100 != 0))
   {
    return true;
   }
   else
   {
    return false;
   }
  }
  #endregion
  #region 判断当前年份是否是闰年，私有函数
  /// <summary>判断当前年份是否是闰年，私有函数</summary>
  /// <param name="dt">年份</param>
  /// <returns>是闰年：True ，不是闰年：False</returns>
  private static bool IsRuYear(int iYear)
  {
   //形式参数为年份
   //例如：2003
   int n;
   n = iYear;
   if ((n % 400 == 0) || (n % 4 == 0 && n % 100 != 0))
   {
    return true;
   }
   else
   {
    return false;
   }
  }
  #endregion
  #region 将输入的字符串转化为日期。如果字符串的格式非法，则返回当前日期
  /// <summary>
  /// 将输入的字符串转化为日期。如果字符串的格式非法，则返回当前日期。
  /// </summary>
  /// <param name="strInput">输入字符串</param>
  /// <returns>日期对象</returns>
  public static DateTime ConvertStringToDate(string strInput)
  {
   DateTime oDateTime;
   try
   {
    oDateTime = DateTime.Parse(strInput);
   }
   catch (Exception)
   {
    oDateTime = DateTime.Today;
   }
   return oDateTime;
  }
  #endregion
  #region 将日期对象转化为格式字符串
  /// <summary>
  /// 将日期对象转化为格式字符串
  /// </summary>
  /// <param name="oDateTime">日期对象</param>
  /// <param name="strFormat">
  /// 格式：
  ///  "SHORTDATE"===短日期
  ///  "LONGDATE"==长日期
  ///  其它====自定义格式
  /// </param>
  /// <returns>日期字符串</returns>
  public static string ConvertDateToString(DateTime oDateTime, string strFormat)
  {
   string strDate = "";
   try
   {
    switch (strFormat.ToUpper())
    {
     case "SHORTDATE":
      strDate = oDateTime.ToShortDateString();
      break;
     case "LONGDATE":
      strDate = oDateTime.ToLongDateString();
      break;
     default:
      strDate = oDateTime.ToString(strFormat);
      break;
    }
   }
   catch (Exception)
   {
    strDate = oDateTime.ToShortDateString();
   }
   return strDate;
  }
  #endregion
  #region 判断是否为合法日期，必须大于1800年1月1日
  /// <summary>
  /// 判断是否为合法日期，必须大于1800年1月1日
  /// </summary>
  /// <param name="strDate">输入日期字符串</param>
  /// <returns>True/False</returns>
  public static bool IsDateTime(string strDate)
  {
   try
   {
    DateTime oDate = DateTime.Parse(strDate);
    if (oDate.CompareTo(DateTime.Parse("1800-1-1")) > 0)
     return true;
    else
     return false;
   }
   catch (Exception)
   {
    return false;
   }
  }
  #endregion
  #region 获取两个日期之间的差值 可返回年 月 日 小时 分钟 秒
  /// <summary>
  /// 获取两个日期之间的差值
  /// </summary>
  /// <param name="howtocompare">比较的方式可为：year month day hour minute second</param>
  /// <param name="startDate">开始日期</param>
  /// <param name="endDate">结束日期</param>
  /// <returns>时间差</returns>
  public static double DateDiff(string howtocompare, DateTime startDate, DateTime endDate)
  {
   double diff = 0;
   try
   {
    TimeSpan TS = new TimeSpan(endDate.Ticks - startDate.Ticks);
    switch (howtocompare.ToLower())
    {
     case "year":
      diff = Convert.ToDouble(TS.TotalDays / 365);
      break;
     case "month":
      diff = Convert.ToDouble((TS.TotalDays / 365) * 12);
      break;
     case "day":
      diff = Convert.ToDouble(TS.TotalDays);
      break;
     case "hour":
      diff = Convert.ToDouble(TS.TotalHours);
      break;
     case "minute":
      diff = Convert.ToDouble(TS.TotalMinutes);
      break;
     case "second":
      diff = Convert.ToDouble(TS.TotalSeconds);
      break;
    }
   }
   catch (Exception)
   {
    diff = 0;
   }
   return diff;
  }
  #endregion
  #region 计算两个日期之间相差的工作日天数
  /// <summary>
  /// 计算两个日期之间相差的工作日天数
  /// </summary>
  /// <param name="dtStart">开始日期</param>
  /// <param name="dtEnd">结束日期</param>
  /// <param name="Flag">是否除去周六，周日</param>
  /// <returns>Int</returns>
  public static int CalculateWorkingDays(DateTime dtStart, DateTime dtEnd, bool Flag)
  {
   int count = 0;
   for (DateTime dtTemp = dtStart; dtTemp < dtEnd; dtTemp = dtTemp.AddDays(1))
   {
    if (Flag)
    {
     if (dtTemp.DayOfWeek != DayOfWeek.Saturday && dtTemp.DayOfWeek != DayOfWeek.Sunday)
     {
      count++;
     }
    }
    else
    {
     count++;
    }
   }
   return count;
  }
  #endregion
 }
}