C#的一些获取时间的例子

 

从周一到周日的顺序，获取排序数值：

int i = datetime.now.dayofweek - dayofweek.monday;
if (i == -1) i = 6;

获取某日起，星期一日期：

public static datetime getmondaydate(datetime somedate)
{
int i = somedate.dayofweek - dayofweek.monday;
if (i == -1) i = 6;// i值 > = 0 ，因为枚举原因，sunday排在最前，此时sunday-monday=-1，必须+7=6。
timespan ts = new timespan(i, 0, 0, 0);
return somedate.subtract(ts);
}

获取当前时间上周六的时间：

public datetime getlastsaturday()
{
datetime time = datetime.now;
if (time.dayofweek == dayofweek.sunday)
{
time = time.adddays(-2);
}
else
time = time.adddays(-1);
while (time.dayofweek != dayofweek.saturday)
{
time = time.adddays(-1);
}
return time;
}