C # yesterday, today, tomorrow, last week, next week, last month, next month, etc.

// Define variables

Private Static datetime currentdatetime; // current time
Private Static datetime lastdatetime; // Yesterday's time
Private Static datetime nextdatetime; // tomorrow's time

Private Static int currentdayofweek; // today's day of the week
Private Static int lastdayofweek; // last day of the week
Private Static int nextdayofweek; // the day of the week tomorrow

Private Static datetime currentstartweek; // Monday of the week
Private Static datetime currentendweek; // Sunday of this week
Private Static datetime currentstartmonth; // the beginning of this month
Private Static datetime currentendmonth; // the end of the month
Private Static datetime currentstartquarter; // The beginning of this quarter
Private Static datetime currentendquarter; // end of this quarter
Private Static datetime currentstartyear; // early this year
Private Static datetime currentendyear; // end of this year

Private Static datetime laststartweek; // Monday of last week
Private Static datetime lastendweek; // last week and Sunday
Private Static datetime laststartmonth; // The beginning of last month
Private Static datetime lastendmonth; // end of last month
Private Static datetime laststartquarter; // the beginning of the last quarter
Private Static datetime lastendquarter; // The end of the last quarter
Private Static datetime laststartyear; // early last year
Private Static datetime lastendyear; // end of last year

Private Static datetime nextstartweek; // Monday of next week
Private Static datetime nextendweek; // Sunday of next week
Private Static datetime nextstartmonth; // early next month
Private Static datetime nextendmonth; // end of next month
Private Static datetime nextstartquarter; // the beginning of the next quarter
Private Static datetime nextendquarter; // end of next quarter
Private Static datetime nextstartyear; // early next year
Private Static datetime nextendyear; // end of next year

 

// Calculate the variable

Currentdatetime = datetime. Now; // current time
Lastdatetime = datetime. Now. adddays (-1); // last day
Nextdatetime = datetime. Now. adddays (1); // tomorrow Time

Currentdayofweek = convert. toint32 (currentdatetime. dayofweek. tostring ("D"); // the day of the week today
Currentdayofweek = convert. toint32 (lastdatetime. dayofweek. tostring ("D"); // the day of the week of yesterday
Currentdayofweek = convert. toint32 (nextdatetime. dayofweek. tostring ("D"); // the day of the week tomorrow

Currentstartweek = currentdatetime. adddays (1-(currentdayofweek = 0 )? 7: currentdayofweek); // Monday of the week
Currentendweek = currentstartweek. adddays (6); // Sunday of the week
Laststartweek = currentstartweek. adddays (-7); // last week, Monday
Lastendweek = currentendweek. adddays (-7); // last week Sunday
Nextstartweek = currentstartweek. adddays (7); // Monday of next week
Nextendweek = currentendweek. adddays (7); // Sunday of the next week

Currentstartmonth = currentdatetime. adddays (1-currentdatetime. Day); // the beginning of this month
Currentendmonth = currentstartmonth. addmonths (1). adddays (-1); // End of the month
Laststartmonth = currentstartmonth. addmonths (-1); // The beginning of last month
Lastendmonth = currentstartmonth. adddays (-1); // last month
Nextstartmonth = currentendmonth. adddays (1); // early next month
Nextendmonth = nextstartmonth. addmonths (1). adddays (-1); // end of next month

Currentstartquarter = currentdatetime. addmonths (0-(currentdatetime. Month-1) % 3). adddays (1-currentdatetime. Day); // at the beginning of this quarter
Currentendquarter = currentstartquarter. addmonths (3). adddays (-1); // end of this quarter
Laststartquarter = currentstartquarter. addmonths (-3); // the beginning of the last quarter
Lastendquarter = currentstartquarter. adddays (-1); // The end of the last quarter
Nextstartquarter = currentendquarter. adddays (1); // the beginning of the next quarter
Nextendquarter = nextstartquarter. addmonths (3). adddays (-1); // end of the next quarter

// Annual calculation
Currentstartyear = new datetime (currentdatetime. Year, 1, 1); // early this year
Currentendyear = new datetime (currentdatetime. year, 12, 31); // end of this year
Laststartyear = currentstartyear. addyears (-1); // early last year
Lastendyear = currentendyear. addyears (-1); // end of last year
Nextstartyear = currentstartyear. addyears (1); // early next year
Nextendyear = currentendyear. addyears (1); // end of next year

 

/// <Summary>
/// Returns the string function of the day of the week.
/// </Summary>
/// <Param name = "mydatetime"> </param>
/// <Returns> </returns>

Private string getweekdayname (datetime mydatetime)
{
String week = "";
// Obtain the current day of the week
String dt = mydatetime. dayofweek. tostring ();
// Returns Chinese Characters Based on the obtained weekly English Words
Switch (DT)
{
Case "Monday ":
Week = "Monday ";
Break;
Case "Tuesday ":
Week = "Tuesday ";
Break;
Case "Wednesday ":
Week = "Wednesday ";
Break;
Case "Thursday ":
Week = "Thursday ";
Break;
Case "Friday ":
Week = "Friday ";
Break;
Case "Saturday ":
Week = "Saturday ";
Break;
Case "Sunday ":
Week = "Sunday ";
Break;
}
Return Week;
}