Date Related Important C# Code & Functions

For This Year Date:

int year = DateTime.Now.Year;
DateTime firstDay = new DateTime(year, 1, 1);
DateTime lastDay = new DateTime(year, 12, 31);
firstDayModified = Convert.ToDateTime(firstDay).ToString("dd-MM-yyyy", CultureInfo.InvariantCulture);
lastDayModified = Convert.ToDateTime(lastDay).ToString("dd-MM-yyyy", CultureInfo.InvariantCulture);
Console.WriteLine("This firstDayModified Start:" + firstDayModified);
Console.WriteLine("This lastDayModified End:" + lastDayModified);

For This Month Date:

DateTime baseDate = DateTime.Today;

var today = baseDate;
var yesterday = baseDate.AddDays(-1);
var thisMonthStart = baseDate.AddDays(1 - baseDate.Day);
var thisMonthEnd = thisMonthStart.AddMonths(1).AddSeconds(-1);

thisMonthStarttModified = Convert.ToDateTime(thisMonthStart).ToString(util.dateFormat4, CultureInfo.InvariantCulture);
thisMonthEndModified = Convert.ToDateTime(thisMonthEnd).ToString(util.dateFormat4, CultureInfo.InvariantCulture);
Console.WriteLine("This Month StartModified:" + thisMonthStarttModified);
Console.WriteLine("This Month EndModified:" + thisMonthEndModified);

For This Week Date:

DateTime baseDate = DateTime.Today;

var today = baseDate;
var yesterday = baseDate.AddDays(-1);
var thisWeekStart = baseDate.AddDays(-(int)baseDate.DayOfWeek);
var thisWeekEnd = thisWeekStart.AddDays(7).AddSeconds(-1);

thisWeekStartModified = Convert.ToDateTime(thisWeekStart).ToString("dd-MM-yyyy", CultureInfo.InvariantCulture);
thisWeekEndModified = Convert.ToDateTime(thisWeekEnd).ToString("dd-MM-yyyy", CultureInfo.InvariantCulture);

Console.WriteLine("This Week thisWeekStartModified:" + thisWeekStartModified);
Console.WriteLine("This Week thisWeekEndModified:" + thisWeekEndModified);

For Todays Date:

DateTime thisDay = DateTime.Today;
string SysDate = thisDay.ToString("d");
createddate = Convert.ToDateTime(SysDate).ToString(util.dateFormat4, CultureInfo.InvariantCulture);
Console.WriteLine("System Date:" + createddate);

Date Parse:

DateTime dt2 = DateTime.ParseExact("31/12/2015", "d/M/yyyy", CultureInfo.InvariantCulture);

Thanks for reading this Code snippet.