时间格式转换

===> 整点报O'Clock  

string strTime = time.ToShortDateString()+" ";

            if (time.Hour <= 12)
            {
                if (time.Minute == 0)
                {
                    strTime += time.Hour.ToString() + " o'clock A.M. ";
                }
                else
                {
                    strTime += time.Hour.ToString() +":"+ time.Minute +" A.M.";
                }

            }
            else//13-23
            {
                if (time.Minute == 0)
                {
                    strTime += (time.Hour - 12) + " o'clock P.M. ";
                }
                else
                {
                    strTime += (time.Hour - 12) + ":" + time.Minute + " P.M. ";
                }
            } 

===> 12/20/2007 01:12:11 PM

DateTime.Now.ToString("MM/dd/yyyy hh:mm:ss tt", System.Globalization.CultureInfo.InvariantCulture);