C#实现的根据日期得到今天是星期几
算法如下：
基姆拉尔森计算公式: W= (d+2*m+3*(m+1)/5+y+y/4-y/100+y/400) mod 7
在公式中d表示日期中的日数，m表示月份数，y表示年数。注意：在公式中有个与其他公式不同的地方：
把一月和二月看成是上一年的十三月和十四月，例：如果是2004-1-10则换算成：2003-13-10来代入公式计算。
但是在测试的时候发现有点出入，就是公式存在一点问题，得稍做修改：
W= (d+2*m+3*(m+1)/5+y+y/4-y/100+y/400) mod 7 +1
#region 根据年月日计算星期几(Label2.Text=CaculateWeekDay(2004,12,9);) /// <summary> /// 根据年月日计算星期几(Label2.Text=CaculateWeekDay(2004,12,9);) /// </summary> /// <param name="y">年</param> /// <param name="m">月</param> /// <param name="d">日</param> /// <returns></returns> public static string CaculateWeekDay(int y,int m, int d) { if(m==1) m=13; if(m==2) m=14; int week=(d+2*m+3*(m+1)/5+y+y/4-y/100+y/400)%7+1; string weekstr=""; switch(week) { case 1: weekstr="星期一"; break; case 2: weekstr="星期二"; break; case 3: weekstr="星期三"; break; case 4: weekstr="星期四"; break; case 5: weekstr="星期五"; break; case 6: weekstr="星期六"; break; case 7: weekstr="星期日"; break; } return weekstr; } #endregion
一周从周日算起 DateTime mDatetime=new DateTime(year,1,1);//year为要求的那一年 int firstweekfirstday=Convert.ToInt32(mDTime.DayOfWeek);//一年中第一天是周几 days=(double)(6-firstweekfirstday); DateTime secondweekfisrtday=mDTime.AddDays(days);第二周一 fisrtday=MDatetime.AddDays(week*7);//第N周第一天 lastday=MDatetime.AddDays(week*7+6);//第N周最后一天 一周从周一算起 DateTime mDatetime=new DateTime(year,1,1);//year为要求的那一年 int firstweekfirstday=Convert.ToInt32(mDTime.DayOfWeek);//一年中第一天是周几 days=(double)(7-firstweekfirstday); DateTime secondweekfisrtday=mDTime.AddDays(days);第二周一 fisrtday=MDatetime.AddDays(week*7);//第N周第一天 lastday=MDatetime.AddDays(week*7+6);//第N周最后一天 javascript: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <HEAD> <TITLE> New Document </TITLE> <SCRIPT LANGUAGE="JavaScript" type="text/javascript"> function showDateCount(year,weekNum){ var date=new Date(year,0,(7*weekNum)); var FD=new Date(date.getYear(),(date.getMonth()),(date.getDate()-date.getDay()+1)) var Monday=FD.getYear()+"-"+(FD.getMonth()+1)+"-"+FD.getDate()//一周的第一天 var LD=new Date(date.getYear(),(date.getMonth()),(date.getDate()-date.getDay()+7)) var Sunday=LD.getYear()+"-"+(LD.getMonth()+1)+"-"+LD.getDate() //一周的最后一天 alert(year+"年第"+weekNum+"周是"+Monday+"至"+Sunday) } </SCRIPT> <META NAME="Generator" CONTENT="EditPlus"> <META NAME="Author" CONTENT=""> <META NAME="Keywords" CONTENT=""> <META NAME="Description" CONTENT=""> </HEAD> <BODY> <input type="text" value="2007" size="20" name="year">年<input type="text" name="weekNum" value="30" size="20"> <input type="button" name="GO" value="Click" onClick="showDateCount(year.value,weekNum.value)"> </BODY> </HTML> c# //monthCalendar1是日历控件 System.Globalization.ChineseLunisolarCalendar c = new ChineseLunisolarCalendar(); private void monthCalendar1_DateChanged(object sender, DateRangeEventArgs e) { DateTime MySelectDate = e.End; txt_nonglidate.Text = string.Format(CultureInfo.InstalledUICulture, "{0}-{1}-{2}", c.GetYear(MySelectDate), c.GetMonth(MySelectDate), c.GetDayOfMonth(MySelectDate)); }
