制作日历-从周日开始的月份将第一周修剪掉

Question

我正在尝试制作一个日历，但是我面临一个问题，从周日开始的月份被切断了他们的第一周。其他一切似乎都可以工作，比如一个月的天数，日期实际上是正确的:

August 2021
MON TUE WED THU FRI SAT SUN
02  03  04  05  06  07  08
09  10  11  12  13  14  15
16  17  18  19  20  21  22
23  24  25  26  27  28  29
30  31

这是我到目前为止的代码:

DateTime displayMonth = new DateTime(2021, 8, 1); // This will be dynamic, ofc.
int firstDay = (int)displayMonth.DayOfWeek;
int cellCounter = 0;
int daysInMonth = (int)DateTime.DaysInMonth(displayMonth.Year, displayMonth.Month);
int weeksInMonth = (int)Math.Ceiling((double)(firstDay + daysInMonth) / 7);
for (var w = 0; w <= weeksInMonth; w++)
{
<div class="row">
@for (var d = 0; d < 7; d++)
{
cellCounter++;
<div class="col">
@{
int day = 1 + cellCounter - firstDay;
if (day > 0 && day <= daysInMonth)
{
<h1>@day</h1>
}
}
</div>
}
</div>
}

Answer 1

我已经知道DayOfWeek和Sunday的指标值为0。我所没有的，是一个"转变"。将星期一改为0:

int firstDay = ((int)displayMonth.DayOfWeek + 6) % 7;

工作代码:

DateTime displayMonth = new DateTime(2021, 9, 1); 
int firstDay = ((int)displayMonth.DayOfWeek + 6) % 7;
int cellCounter = 0;
int daysInMonth = (int)DateTime.DaysInMonth(displayMonth.Year, displayMonth.Month);
int weeksInMonth = (int)Math.Ceiling((double)(firstDay + daysInMonth) / 7);
for (var w = 0; w <= weeksInMonth; w++)
{
<div class="row">
@for (var d = 0; d < 7; d++)
{
cellCounter++;
<div class="col">
@{
int day = cellCounter - firstDay;
if (day > 0 && day <= daysInMonth)
{
<h1>@day</h1>
}
}
</div>
}
</div>
}