如何計算未來某個特定時期的日期？

Question

我有這樣的：

string dataNow = DateTime.Today.tostring(); 
string dateAfter = dateNow + (20 days); 

如何找到在20天的日期？
如何查找當月的天數？

Answer 1

您的可能意圖是使用日期作爲日期類型DateTime。在這種情況下，不叫ToString()你完成操作的日期前：

string dataNow = DateTime.Today.AddDays(20).ToString(); 

DateTime.AddDays

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更新後：

要獲得當月的天數：

var date = DateTime.Today; 
int days = DateTime.DaysInMonth(date.Year, date.Month); 

DateTime.DaysInMonth

Answer 2

這應做到：

DateTime dtNow = DateTime.Today; 
    string dateNow = dtNow.ToString(); 
    string dateAfter = dtNow.AddDays(20).ToString(); 
    int DaysInTheMonth = DateTime.DaysInMonth(dtNow.Year, dtNow.Month); 

Answer 3

DateTime today = DateTime.Today; 
DateTime later = today.AddDays(20); 

string todayAsString = today.ToString("d"); 
string laterAsString = later.ToString("d"); 

int daysThisMonth = DateTime.DaysInMonth(today.Year, today.Month); 
int daysLaterMonth = DateTime.DaysInMonth(later.Year, later.Month);