我怎样才能找出一个月中的第几天？

Question

我必须找出给定日期的日期，假设我有 01/26/2020 日期，现在日期 26 是该月的第 4 个星期日，我如何通过它的可重复计数找出日期在一个月内？

Answer 1

没有直接实现的方法that.You需要调用类似下面的代码

 DateTime dateValue = new DateTime(2019, 12, 19);
        int getDayOfWeek = GetWeekNumberOfMonth(dateValue);
        //convert to ordinal 
       string ordinalWeekOfMonth = AddOrdinal(getDayOfWeek);
      Console.WriteLine(ordinalWeekOfMonth + " " + dateValue.DayOfWeek);//output like 2nd sunday

下面的依赖方法可以用来调用上面的代码

     public static int GetWeekNumberOfMonth(DateTime date)
    {
        date = date.Date;
        DateTime firstMonthDay = new DateTime(date.Year, date.Month, 1);
        DateTime firstMonthMonday = firstMonthDay.AddDays((DayOfWeek.Monday + 7 - firstMonthDay.DayOfWeek) % 7);
        if (firstMonthMonday > date)
        {
            firstMonthDay = firstMonthDay.AddMonths(-1);
            firstMonthMonday = firstMonthDay.AddDays((DayOfWeek.Monday + 7 - firstMonthDay.DayOfWeek) % 7);
        }
        return (date - firstMonthMonday).Days / 7 + 1;
    }

    public static string AddOrdinal(int num)
    {
        if (num <= 0) return num.ToString();

        switch (num % 100)
        {
            case 11:
            case 12:
            case 13:
                return num + "th";
        }

        switch (num % 10)
        {
            case 1:
                return num + "st";
            case 2:
                return num + "nd";
            case 3:
                return num + "rd";
            default:
                return num + "th";
        }

    }

我怎样才能找出一个月中的第几天？

how can I find out the day of the month?

c#

date

dayofweek

dayofmonth