Asp.net 時間操作基類(短日期,長日期,時間差)

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 EC
{
    /// <summary>
    /// 時間操作函數
    /// </summary>
    public class TimeObject
    {
        /// <summary>
        /// 時間差
        /// </summary>
        /// <param name="starttime">開始時間</param>
        /// <param name="endtime">結束時間</param>
        /// <returns></returns>
        public static string GetTimeSpan(DateTime starttime, DateTime endtime)
        {
            TimeSpan ts = endtime - starttime;
            return string.Format("{0}時{1}分{2}秒{3}毫秒", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds);
        }

        /// <summary>
        /// 轉稱為月-日:09-12
        /// </summary>
        /// <param name="d">日期</param>
        /// <returns></returns>
        public static string ToDateMonthDay(DateTime d)
        {
            return d.ToString("MM-dd");
        }
        /// <summary>
        /// 轉換為年月日:2006-09-12
        /// </summary>
        /// <param name="d"></param>
        /// <returns></returns>
        public static string ToDateString(DateTime d)
        {
            return d.ToString("yyyy-MM-dd");
        }
        /// <summary>
        /// 轉換為:小時:分:秒 00:29:58
        /// </summary>
        /// <param name="t"></param>
        /// <returns></returns>
        public static string ToTimeString(DateTime t)
        {
            return t.ToString("HH:mm:ss");
        }
        /// <summary>
        /// 轉換為長時間:2006-09-12 00:30:57
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string ToDateTimeString(DateTime dt)
        {
            return dt.ToString("yyyy-MM-dd HH:mm:ss");
        }    

   
    }

}