DateTime 结构

1var dateTimeDefault = new DateTime(); // The minimum value
2Console.WriteLine(dateTimeDefault);
3
4var anotherDateTime = DateTime.MinValue; // The minimum value
5Console.WriteLine(anotherDateTime);

1int year = 2021;
2int month = 12;
3int day = 24;
4int hour = 12;
5int minute = 27;
6int second = 45;
7
8var dateWithoutTime = new DateTime(year, month, day);
9Console.WriteLine(dateWithoutTime);
10
11var dateAndTime = new DateTime(year, month, day, hour, minute, second);
12Console.WriteLine(dateAndTime);

1var currentDate = DateTime.Today;
2Console.WriteLine(currentDate);
3
4var currentDateAndTime = DateTime.Now;
5Console.WriteLine(currentDateAndTime);
6
7var currentDateAndTimeInUtc = DateTime.UtcNow;
8Console.WriteLine(currentDateAndTimeInUtc);

1var someDate = new DateTime(1970, 2, 12);
2Console.WriteLine($"{someDate} was {someDate.DayOfWeek}.");
3
4var suffix = GetNumberSuffix(someDate.DayOfYear);
5Console.WriteLine($"It was the {someDate.DayOfYear}{suffix} day of the year.");
6
7// Local function defined at the bottom of our top-level statements
8static string GetNumberSuffix(int number)
9{
10    string suffix;
11
12    if (number == 11 || number == 12 || number == 13)
13    {
14        suffix = "th";
15    }
16    else if (number % 10 == 1)
17    {
18        suffix = "st";
19    }
20    else if (number % 10 == 2)
21    {
22        suffix = "nd";
23    }
24    else if (number % 10 == 3)
25    {
26        suffix = "rd";
27    }
28    else
29    {
30        suffix = "th";
31    }
32
33    return suffix;
34}

1var birthDate = new DateTime(1970, 2, 12);
2Console.WriteLine(birthDate);
3
4var fortyDaysAfterBirthDate = birthDate.AddDays(40);
5Console.WriteLine(fortyDaysAfterBirthDate);