this.timer2.Stop();
DateTime CTime=DateTime.Today;
TimeSpan Ts=new TimeSpan             (0,this.hourStr,this.minuteStr,this.minsecStr,0);
DateTime SendTime=CTime.Add(Ts);
if(DateTime.Now.Equals(SendTime))
{   
//运行函数
}
            this.timer2.Start();
不过请注意在是asp.net运行不了的