Lesson #13 - The DateTime Class

Updated: Dec 13, 2020

The DateTime class is very important as I provide a different way to manage time and dates as part of the execution process of the program. To understand the importance and capabilities of this class let’s see some examples.


Example 1: Extracting Date/Time information


class Program

{

static void Main(string[] args)

{

//Example 1: Extracting Date/Time information

Console.ForegroundColor = ConsoleColor.Green;

Console.WriteLine("Current Time :" + DateTime.Now);

Console.ResetColor();

Console.WriteLine("\nExtract Date: " + DateTime.Now.Date);

Console.WriteLine("Extract current year: " + DateTime.Now.Year);

Console.WriteLine("Extract Day of year: " + DateTime.Now.DayOfYear);

Console.WriteLine("Extract current month " + DateTime.Now.Month);

Console.WriteLine("Extract Day(Number): " + DateTime.Now.Day);

Console.WriteLine("Extract Day of week : " + DateTime.Now.DayOfWeek);

Console.WriteLine("Extract current hour: " + DateTime.Now.Hour);

Console.WriteLine("Extract current minute: " + DateTime.Now.Minute);

Console.WriteLine("Extract current second: " + DateTime.Now.Second);

Console.ReadKey();

}

}

Result:


Example 2: Creating a DateTime instance with a contractor and without


class Program

{

static void Main(string[] args)

{

//Example 1: Default value for a class instance

DateTime DateTimeDefaultValue = new DateTime();

Console.WriteLine("Example 1: Default Value of an instance is: " + DateTimeDefaultValue);


//Example 2: Initialization using the class Constructor(1)

DateTime MyBirthDay = new DateTime(1984,5,31);

Console.WriteLine("Example 2: My Birth Day is: " + MyBirthDay);


//Example 3: Initialization using the class Constructor(2)

DateTime MyBirthDayIncludingTime = new DateTime(1984, 5, 31,22,32,42);

Console.WriteLine("Example 3: My time of birth is: " + MyBirthDayIncludingTime);


//Example 4: Creating instance based on a specific calendar

TaiwanLunisolarCalendar TaiwanLunisolarCalendar_CalanderCal = new TaiwanLunisolarCalendar();

DateTime Ta_Calander = new DateTime(100, 6, 6, TaiwanLunisolarCalendar_CalanderCal);

Console.WriteLine("Example 4: Time Based on Taiwan calendar: " + Ta_Calander);

Console.ReadKey();

}

}


Result:


Example 3: Working with specific date parts


class Program

{

static void Main(string[] args)

{

//Get the current date and time

Console.ForegroundColor = ConsoleColor.Green;

Console.WriteLine("Current Time :" + DateTime.Now +"\n");

Console.ResetColor();


//Editing specific parts of the returned values

Console.WriteLine("Current Date + 1 Year: " + DateTime.Now.AddYears(1));

Console.WriteLine("Current Date - 20 Years: " + DateTime.Now.AddYears(-20));

Console.WriteLine("Current Date + 2 Months: " + DateTime.Now.AddMonths(2));

Console.WriteLine("Current Date - 2 Months: " + DateTime.Now.AddMonths(-2));

Console.WriteLine("Current Date + 3 Days: " + DateTime.Now.AddDays(3));

Console.WriteLine("Current Date - 3 Days: " + DateTime.Now.AddDays(-3));

Console.ReadKey();

}

}


Result:


Example 4:


class Program

{

static void Main(string[] args)

{

//Get the current date and time

Console.ForegroundColor = ConsoleColor.Green;

Console.WriteLine("Current Time :" + DateTime.Now);

Console.ResetColor();

Console.WriteLine();


//Main methods for time modifications

Console.WriteLine("Current Time + 10 Hours: " + DateTime.Now.AddHours(10));

Console.WriteLine("Current Time - 10 Hours: " + DateTime.Now.AddHours(-10));

Console.WriteLine("Current Time + 5 Minutes: " + DateTime.Now.AddMinutes(5));

Console.WriteLine("Current Time - 5 Minutes: " + DateTime.Now.AddMinutes(-5));

Console.WriteLine("Current Time + 30 Seconds: " + DateTime.Now.AddSeconds(30));

Console.WriteLine("Current Time - 30 Seconds: " + DateTime.Now.AddSeconds(-30));


Console.ReadKey();

}

}


Result:


Example 5: How can we Compare dates?


class Program

{

static void Main(string[] args)

{

DateTime TheFirstDate = new DateTime(2010, 1, 1, 1, 1, 1);

DateTime TheSecondDate = new DateTime(1900, 2, 2, 2, 2, 2);

DateTime TheThirdDate = new DateTime(1900, 2, 2, 2, 2, 2);

//Calling the Comparing method:

CompareDates(TheFirstDate, TheSecondDate);

CompareDates(TheSecondDate, TheThirdDate);

CompareDates(TheThirdDate, TheFirstDate);

Console.ReadKey();

}

private static void CompareDates(DateTime InsertDate1, DateTime insertDate2)

{

int Comapring_results = DateTime.Compare(InsertDate1, insertDate2);

/*

Expected results:

0 = Identical Dates

- = TheFirstDate < TheSecondDate

+ = TheFirstDate > TheSecondDate

*/


if (Comapring_results == 0)

{

Console.ForegroundColor = ConsoleColor.Yellow;

Console.WriteLine("Dates are Equal");

Console.ResetColor();

}

if (Comapring_results < 0)

{

Console.ForegroundColor = ConsoleColor.Red;

Console.WriteLine("Date_1 is smaller than Date_2");

Console.ResetColor();

}

if (Comapring_results > 0)

{

Console.ForegroundColor = ConsoleColor.Green;

Console.WriteLine("Date_1 is bigger than Date_2");

Console.ResetColor();

}

}

}


Result:



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