C#中用当前日期算周的若干问题?

Posted 2023-05-15

问题1：
知道当前日期算是星期几？
一定要正确啊！
问题2：
算当前日期属于第几周？
规则：若是每月的1号是周一，二，三，四，则：该1号是该月的第一周，
若是每月的1号是周五，周六，周日，则：该月的第一周从4号开始。
我也想该怎么写，先与大家分享一下问题！

Q1:DateTime.Now.DayOfWeek
Q2:private int getWeeksOfDayInMonth(DateTime dt)

DateTime monthFirstDay = DateTime.Parse(dt.Year.ToString() + "-" + dt.Month.ToString() + "-1");
int startDay = 1;//第一周从哪天开始
int dayOfOneWeek = 0;//第一周有几天
switch (monthFirstDay.DayOfWeek)

case DayOfWeek.Monday: dayOfOneWeek = 7; startDay = 1;
break;
case DayOfWeek.Tuesday: dayOfOneWeek = 6; startDay = 1;
break;
case DayOfWeek.Wednesday: dayOfOneWeek = 5; startDay = 1;
break;
case DayOfWeek.Thursday: dayOfOneWeek = 4; startDay = 1;
break;
case DayOfWeek.Friday: dayOfOneWeek = 7; startDay = 4;
break;
case DayOfWeek.Saturday: dayOfOneWeek = 7; startDay = 3;
break;
case DayOfWeek.Sunday: dayOfOneWeek = 7; startDay = 2;
break;

int returnValue = 0;
int span = dt.Day - startDay;
if (span < 0)
returnValue = 0;
else
returnValue = span < dayOfOneWeek ? 1 : ((span - dayOfOneWeek) / 7 + 2);
return returnValue;
参考技术A DateTime.Now.DayOfWeek

第二个问题的话你就要加上自己的判断逻辑了!

layui日期选择框实现选择当前周的日期范围

直接上代码：

layui.use(['laydate'], function() 
	var laydate = layui.laydate;
	var monday = getMonday(new Date());
    var mm = layui.util.toDateString(monday,'yyyy-MM-dd')
    var sunday = GetDateStr(monday,6);
	laydate.render(
            elem: '#daterange'//绑定的html元素id
            ,type:'date'
            ,format: 'yyyy-MM-dd' //格式
            ,trigger : 'click'
            ,min:mm //最小可选择日期
            ,max:sunday //最大可选择日期
            ,range:true //设置启用日期范围
        );
 )
 //获取当前日期的周一日期
 function getMonday( date ) 
    		var day = date.getDay() || 7;  
    		if( day !== 1 ) 
        	date.setHours(-24 * (day - 1)); 
    		return date;
		
//获取某日期的第n天后的日期
 function GetDateStr(date,n)    
   			var dd = date;  
   			dd.setDate(dd.getDate()+n);  
   			var y = dd.getFullYear();   
   			var m = (dd.getMonth()+1)<10?"0"+(dd.getMonth()+1):(dd.getMonth()+1);
   			var d = dd.getDate()<10?"0"+dd.getDate():dd.getDate();
			return y+"-"+m+"-"+d;   
		;