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Maximum integer value find in list<int>
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Closed 4 years ago.
I am using WebClient to retrieve a set of data. After receiving the data, I need to loop trough it. I need to know the what was the maximum value of date within the data, so new data can be retrieved from following date.
Simplified, my code looks like:
class MyClass
{
public DateTime LoopDate()
{
DateTime[] TripDates = { DateTime.Parse("2019-01-01"), DateTime.Parse("2019-01-02"), DateTime.Parse("2019-01-03") };
DateTime maxdate;
foreach (var date in TripDates)
{
maxdate = date;
Console.WriteLine(date);
}
return maxdate; //needs to return the maximum DateTime value from the loop
}
}
class Program
{
static void Main(string[] args)
{
var MyClass = new MyClass();
var Nextdate = MyClass.LoopDate();
Console.ReadKey();
}
}
public DateTime LoopDate()
{
DateTime[] TripDates = { DateTime.Parse("2019-01-01"), DateTime.Parse("2019-01-02"), DateTime.Parse("2019-01-03") };
DateTime maxdate = TripDates.Max();
return maxdate; //needs to return the maximum DateTime value from the loop
}
The below line will work for you
DateTime maxdate = TripDates.Max();
I want to get the first day and last day of the month where a given date lies in. The date comes from a value in a UI field.
If I'm using a time picker I could say
var maxDay = dtpAttendance.MaxDate.Day;
But I'm trying to get it from a DateTime object. So if I have this...
DateTime dt = DateTime.today;
How to get first day and last day of the month from dt?
DateTime structure stores only one value, not range of values. MinValue and MaxValue are static fields, which hold range of possible values for instances of DateTime structure. These fields are static and do not relate to particular instance of DateTime. They relate to DateTime type itself.
Suggested reading: static (C# Reference)
UPDATE: Getting month range:
DateTime date = ...
var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
var lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddDays(-1);
UPDATE: From comments (#KarlGjertsen & #SergeyBerezovskiy)
DateTime date = ...
var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
var lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddSeconds(-1);
//OR
var lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddTicks(-1);
This is more a long comment on #Sergey and #Steffen's answers. Having written similar code myself in the past I decided to check what was most performant while remembering that clarity is important too.
Result
Here is an example test run result for 10 million iterations:
2257 ms for FirstDayOfMonth_AddMethod()
2406 ms for FirstDayOfMonth_NewMethod()
6342 ms for LastDayOfMonth_AddMethod()
4037 ms for LastDayOfMonth_AddMethodWithDaysInMonth()
4160 ms for LastDayOfMonth_NewMethod()
4212 ms for LastDayOfMonth_NewMethodWithReuseOfExtMethod()
2491 ms for LastDayOfMonth_SpecialCase()
Code
I used LINQPad 4 (in C# Program mode) to run the tests with compiler optimization turned on. Here is the tested code factored as Extension methods for clarity and convenience:
public static class DateTimeDayOfMonthExtensions
{
public static DateTime FirstDayOfMonth_AddMethod(this DateTime value)
{
return value.Date.AddDays(1 - value.Day);
}
public static DateTime FirstDayOfMonth_NewMethod(this DateTime value)
{
return new DateTime(value.Year, value.Month, 1);
}
public static DateTime LastDayOfMonth_AddMethod(this DateTime value)
{
return value.FirstDayOfMonth_AddMethod().AddMonths(1).AddDays(-1);
}
public static DateTime LastDayOfMonth_AddMethodWithDaysInMonth(this DateTime value)
{
return value.Date.AddDays(DateTime.DaysInMonth(value.Year, value.Month) - value.Day);
}
public static DateTime LastDayOfMonth_SpecialCase(this DateTime value)
{
return value.AddDays(DateTime.DaysInMonth(value.Year, value.Month) - 1);
}
public static int DaysInMonth(this DateTime value)
{
return DateTime.DaysInMonth(value.Year, value.Month);
}
public static DateTime LastDayOfMonth_NewMethod(this DateTime value)
{
return new DateTime(value.Year, value.Month, DateTime.DaysInMonth(value.Year, value.Month));
}
public static DateTime LastDayOfMonth_NewMethodWithReuseOfExtMethod(this DateTime value)
{
return new DateTime(value.Year, value.Month, value.DaysInMonth());
}
}
void Main()
{
Random rnd = new Random();
DateTime[] sampleData = new DateTime[10000000];
for(int i = 0; i < sampleData.Length; i++) {
sampleData[i] = new DateTime(1970, 1, 1).AddDays(rnd.Next(0, 365 * 50));
}
GC.Collect();
System.Diagnostics.Stopwatch sw = System.Diagnostics.Stopwatch.StartNew();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].FirstDayOfMonth_AddMethod();
}
string.Format("{0} ms for FirstDayOfMonth_AddMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].FirstDayOfMonth_NewMethod();
}
string.Format("{0} ms for FirstDayOfMonth_NewMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_AddMethod();
}
string.Format("{0} ms for LastDayOfMonth_AddMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_AddMethodWithDaysInMonth();
}
string.Format("{0} ms for LastDayOfMonth_AddMethodWithDaysInMonth()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_NewMethod();
}
string.Format("{0} ms for LastDayOfMonth_NewMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_NewMethodWithReuseOfExtMethod();
}
string.Format("{0} ms for LastDayOfMonth_NewMethodWithReuseOfExtMethod()", sw.ElapsedMilliseconds).Dump();
for(int i = 0; i < sampleData.Length; i++) {
sampleData[i] = sampleData[i].FirstDayOfMonth_AddMethod();
}
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_SpecialCase();
}
string.Format("{0} ms for LastDayOfMonth_SpecialCase()", sw.ElapsedMilliseconds).Dump();
}
Analysis
I was surprised by some of these results.
Although there is not much in it the FirstDayOfMonth_AddMethod was slightly faster than FirstDayOfMonth_NewMethod in most runs of the test. However, I think the latter has a slightly clearer intent and so I have a preference for that.
LastDayOfMonth_AddMethod was a clear loser against LastDayOfMonth_AddMethodWithDaysInMonth, LastDayOfMonth_NewMethod and LastDayOfMonth_NewMethodWithReuseOfExtMethod. Between the fastest three there is nothing much in it and so it comes down to your personal preference. I choose the clarity of LastDayOfMonth_NewMethodWithReuseOfExtMethod with its reuse of another useful extension method. IMHO its intent is clearer and I am willing to accept the small performance cost.
LastDayOfMonth_SpecialCase assumes you are providing the first of the month in the special case where you may have already calculated that date and it uses the add method with DateTime.DaysInMonth to get the result. This is faster than the other versions, as you would expect, but unless you are in a desperate need for speed I don't see the point of having this special case in your arsenal.
Conclusion
Here is an extension method class with my choices and in general agreement with #Steffen I believe:
public static class DateTimeDayOfMonthExtensions
{
public static DateTime FirstDayOfMonth(this DateTime value)
{
return new DateTime(value.Year, value.Month, 1);
}
public static int DaysInMonth(this DateTime value)
{
return DateTime.DaysInMonth(value.Year, value.Month);
}
public static DateTime LastDayOfMonth(this DateTime value)
{
return new DateTime(value.Year, value.Month, value.DaysInMonth());
}
}
If you have got this far, thank you for time! Its been fun :¬). Please comment if you have any other suggestions for these algorithms.
Getting month range with .Net API (just another way):
DateTime date = ...
var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
var lastDayOfMonth = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
"Last day of month" is actually "First day of *next* month, minus 1". So here's what I use, no need for "DaysInMonth" method:
public static DateTime FirstDayOfMonth(this DateTime value)
{
return new DateTime(value.Year, value.Month, 1);
}
public static DateTime LastDayOfMonth(this DateTime value)
{
return value.FirstDayOfMonth()
.AddMonths(1)
.AddMinutes(-1);
}
NOTE:
The reason I use AddMinutes(-1), not AddDays(-1) here is because usually you need these date functions for reporting for some date-period, and when you build a report for a period, the "end date" should actually be something like Oct 31 2015 23:59:59 so your report works correctly - including all the data from last day of month.
I.e. you actually get the "last moment of the month" here. Not Last day.
OK, I'm going to shut up now.
DateTime dCalcDate = DateTime.Now;
dtpFromEffDate.Value = new DateTime(dCalcDate.Year, dCalcDate.Month, 1);
dptToEffDate.Value = new DateTime(dCalcDate.Year, dCalcDate.Month, DateTime.DaysInMonth(dCalcDate.Year, dCalcDate.Month));
Here you can add one month for the first day of current month than delete 1 day from that day.
DateTime now = DateTime.Now;
var startDate = new DateTime(now.Year, now.Month, 1);
var endDate = startDate.AddMonths(1).AddDays(-1);
If you only care about the date
var firstDay = new DateTime(date.Year, date.Month, 1, 0, 0, 0, date.Kind);
var lastDay = new DateTime(date.Year, date.Month, 1, 0, 0, 0, date.Kind).AddMonths(1).AddDays(-1);
If you want to preserve time
var firstDay = new DateTime(date.Year, date.Month, 1, date.Hour, date.Minute, date.Second, date.Kind);
var lastDay = new DateTime(date.Year, date.Month, 1, date.Hour, date.Minute, date.Second, date.Kind).AddMonths(1).AddDays(-1);
Try this one:
string strDate = DateTime.Now.ToString("MM/01/yyyy");
The accepted answer here does not take into account the Kind of the DateTime instance. For example if your original DateTime instance was a UTC Kind then by making a new DateTime instance you will be making an Unknown Kind instance which will then be treated as local time based on server settings. Therefore the more proper way to get the first and last date of the month would be this:
var now = DateTime.UtcNow;
var first = now.Date.AddDays(-(now.Date.Day - 1));
var last = first.AddMonths(1).AddTicks(-1);
This way the original Kind of the DateTime instance is preserved.
I used this in my script(works for me) but I needed a full date without the need of trimming it to only the date and no time.
public DateTime GetLastDayOfTheMonth()
{
int daysFromNow = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month) - (int)DateTime.Now.Day;
return DateTime.Now.AddDays(daysFromNow);
}
For Persian culture
PersianCalendar pc = new PersianCalendar();
var today = pc.GetDayOfMonth(DateTime.Now);
var firstDayOfMonth = pc.GetDayOfMonth(DateTime.Now.AddDays(-(today-1)));
var lastDayOfMonth = pc.GetDayOfMonth(DateTime.Now.AddMonths(1).AddDays(-today));
Console.WriteLine("First day "+ firstDayOfMonth);
Console.WriteLine("Last day " + lastDayOfMonth);
You can do it
DateTime dt = DateTime.Now;
DateTime firstDayOfMonth = new DateTime(dt.Year, date.Month, 1);
DateTime lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddDays(-1);
Give this a try. It basically calculates the number of days that has passed on DateTime.Now, then subtracts one from that and uses the new value to find the first of the current month. From there it uses that DateTime and uses .AddMonths(-1) to get the first of the previous month.
Getting the last day of last month does basically the same thing except it adds one to number of days in the month and subtracts that value from DateTime.Now.AddDays, giving you the last day of the previous month.
int NumberofDays = DateTime.Now.Day;
int FirstDay = NumberofDays - 1;
int LastDay = NumberofDays + 1;
DateTime FirstofThisMonth = DateTime.Now.AddDays(-FirstDay);
DateTime LastDayOfLastMonth = DateTime.Now.AddDays(-LastDay);
DateTime CheckLastMonth = FirstofThisMonth.AddMonths(-1);
You can try this for get current month first day;
DateTime.Now.AddDays(-(DateTime.Now.Day-1))
and assign it a value.
Like this:
dateEndEdit.EditValue = DateTime.Now;
dateStartEdit.EditValue = DateTime.Now.AddDays(-(DateTime.Now.Day-1));
Create an instance of DateTime class
DateTime dateTime = DateTime.Now;
If you want to get the last day of the month you can do this
int lastDayOfMonth = DateTime.DaysInMonth(caducidadPuntos.Year, caducidadPuntos.Month);
If you want to get the first day of the month, you can do this
DateTime firstDayMonth = new DateTime(dateTime.Year, dateTime.Month, 1);
We had the requirement of being able to get the start and end of a given dates month, including times, inclusively. We ended up utilizing the aforementioned solutions, huge thanks to everyone here, and combined it into a util class to be able to get the start and end for a given month and year number combination up to the last millisecond. Including what we moved forward with in the event it helps someone else.
The util:
public class DateUtil
{
public static (DateTime startOfMonth, DateTime endOfMonth) GetStartAndEndOfMonth(int month, int year)
{
DateTime startOfMonth = GetStartOfMonth(month, year);
DateTime endOfMonth = GetEndOfMonth(month, year);
return (startOfMonth, endOfMonth);
}
public static DateTime GetStartOfMonth(int month, int year)
{
return new DateTime(year, month, 1).Date;
}
public static DateTime GetEndOfMonth(int month, int year)
{
return new DateTime(year, month, 1).Date.AddMonths(1).AddMilliseconds(-1);
}
}
Usage:
(DateTime startOfMonth, DateTime endOfMonth) = DateUtil.GetStartAndEndOfMonth(2, 2021); // February, 2021
easy way to do it
Begin = new DateTime(DateTime.Now.Year, DateTime.Now.Month,1).ToShortDateString();
End = new DataFim.Text = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month)).ToShortDateString();
DateTime dCalcDate = DateTime.Now;
var startDate = new DateTime(Convert.ToInt32(Year), Convert.ToInt32(Month), 1);
var endDate = new DateTime(Convert.ToInt32(Year), Convert.ToInt32(Month), DateTime.DaysInMonth((Convert.ToInt32(Year)), Convert.ToInt32(Month)));
I am currently want to get the date range (between time range) from the list of dates.
For example:
The time now is
2017-04-08 18:00
And I got these from and to dates:
public static string[] fromDates = new string[] { "2017-04-07 07:00", "2017-04-07 10:00", "2017-04-07 12:00", "2017-04-07 14:00", "2017-04-07 16:00" };
public static string[] toDates = new string[] { "2017-04-07 08:00", "2017-04-07 11:00", "2017-04-07 13:00", "2017-04-07 15:00", "2017-04-07 17:00" };
I am using this code:
public static bool IsInRange(this DateTime dateToCheck, string[] startDates, string[] endDates, out string StartDate, out string EndDate)
{
DateTime startDate = new DateTime();
DateTime endDate = new DateTime();
bool isWithinRange = false;
for (int i = 0; i < startDates.Length; i++)
{
startDate = Convert.ToDateTime(startDates[i]);
isWithinRange = dateToCheck >= startDate;
if (isWithinRange)
break;
}
for (int y = 0; y < endDates.Length; y++)
{
endDate = Convert.ToDateTime(endDates[y]);
isWithinRange = dateToCheck < endDate;
if (isWithinRange)
break;
}
StartDate = startDate;
EndDate = endDate;
return isWithinRange;
}
And I call it like this:
var isBetween = Convert.ToDateTime("2017-04-08 18:00").IsInRange(fromDates, toDates, out StartDate, out EndDate)
But I couldn't make it working, the StartDate in IsInRange method is always return true and it will return the first index from fromDates variable, which is wrong.
How can I make it like the time between?
I know I can do it like this:
var isBetween = dateToCheck >= startDate && dateToCheck < endDate
But it is only one date need to check, what about if it is like my situation?
Your answer much appreciated.
Thanks
I would start by converting everything into a more useful object model:
Get rid of all the strings (i.e. convert from strings to something more useful early on)
Instead of having two collections, create a new type indicating "a date/time range". You're being somewhat foiled by relating the wrong items together: the start values aren't related to each other, they're related to their corresponding end dates.
You could do this within the method if you really need to, but it would be better to move to a richer object model for as much of your code as you can. For example, suppose you have:
public sealed class DateTimeRange
{
public DateTime Start { get; }
public DateTime End { get; }
public DateTimeRange(DateTime start, DateTime end)
{
// TODO: Validate that start <= end
Start = start;
End = end;
}
public bool Contains(DateTime value) => Start <= value && value < End;
}
Then your method can look like this:
public DateTimeRange FindRange(IEnumerable<DateTimeRange> ranges, DateTime value) =>
ranges.FirstOrDefault(range => range.Contains(value));
That will return null if no ranges contain the value, or the first one that does contain a value otherwise.
(As an aside, I'd do all of this in Noda Time instead as a better date/time API, but I'm biased.)
If you want to stay with yoir design, then you should simply do everything inside one loop, instead of doing it twice, as you want always to match first element with first element, second with second etc.
public static bool IsInRange(this DateTime dateToCheck, string[] startDates, string[] endDates, out DateTime StartDate, out DateTime EndDate)
{
if (startDates.Length != endDates.Length)
{
throw new ArgumentException("The arrays must have the same length");
}
StartDate = new DateTime();
EndDate = new DateTime();
for (int i = 0; i < startDates.Length; i++)
{
StartDate = Convert.ToDateTime(startDates[i]);
EndDate = Convert.ToDateTime(endDates[i]);
if (dateToCheck >= StartDate && dateToCheck <= EndDate)
{
return true;
}
}
return false;
}
But as already stated in other answer - you should redesign your code, because it's not very maintenable and easy to understand
I have the following datetimes:
Start = 15/12/2012 13:00:00
End = 16/02/2013 14:00:00
How can I split that in 3 parts for each month?
- 15-12-2012 13:00:00 -> 01-01-2013 00:00:00
- 01-01-2013 00:00:00 -> 01-02-2013 00:00:00
- 01-02-2013 00:00:00 -> 16-02-2013 14:00:00
The total timespan must remain the same.
Can this easily be done with LINQ?
sure, try this (with little helper class included)
Process:
var Start = DateTime.Parse("15 Dec 2012 13:00:00");
var End = DateTime.Parse("16 Feb 2013 14:00:00");
var runningDate = Start;
while (runningDate < End)
{
var nextMonthSeed = runningDate.AddMonths(1);
var to = DateHelper.Min(new DateTime(nextMonthSeed.Year, nextMonthSeed.Month, 1), End);
Console.WriteLine("{0} -> {1}", runningDate.ToString("dd-MM-yyyy HH:mm:ss"), to.ToString("dd-MM-yyyy HH:mm:ss"));
runningDate = to;
}
Helper class:
public static class DateHelper
{
public static DateTime Min(DateTime date1, DateTime date2)
{
return (date1 < date2 ? date1 : date2);
}
}
You could try something like these extension methods:
public static class SomeExtensions {
public static IEnumerable<Tuple<DateTime, DateTime>> GetIntervals(
this DateTime from,
DateTime to) {
var currentFrom = from;
var currentTo = from.AdvanceToStartOfNextMonth();
while (currentTo < to) {
yield return Tuple.Create(currentFrom, currentTo);
currentFrom = currentTo;
currentTo = currentFrom.AdvanceToStartOfNextMonth();
}
yield return Tuple.Create(currentFrom, to);
}
public static DateTime AdvanceToStartOfNextMonth(this DateTime #this) {
var newMonth = #this.Month + 1;
var newYear = #this.Year;
if (newMonth == 13) {
newMonth = 1;
newYear++;
}
return new DateTime(newYear, newMonth, 1);
}
}
and then use them like so:
public class Etc {
public static void Foo() {
DateTime start = ...
DateTime stop = ....
Tuple<DateTime, DateTime>[] intervals = start.GetIntervals(stop).ToArray();
// or simply
foreach (var interval in start.GetIntervals(stop))
Console.WriteLine(interval);
}
}
EDIT
And here's a little test I just tried out (and it looks alright, I think):
class Program {
static void Main(string[] args) {
DateTime start = DateTime.Now.Subtract(TimeSpan.FromDays(170));
DateTime stop = DateTime.Now;
foreach (var interval in start.GetIntervals(stop))
Console.WriteLine(interval);
Console.ReadKey(intercept: true);
}
}
and that produced these results (in a console app):
END OF EDIT
I want to extract all the sundays in the current month and have this code:
private string GetDatesOfSundays(DateTime DatMonth)
{
string sReturn = "";
int iDayOffset = DatMonth.Day - 1;
DatMonth = DatMonth.AddDays(System.Convert.ToDouble(-DatMonth.Day + 1));
DateTime DatMonth2 = DatMonth.AddMonths(1).AddDays(System.Convert.ToDouble(-1));
while (DatMonth < DatMonth2)
{
if (DatMonth.DayOfWeek == System.DayOfWeek.Sunday)
{
if (sReturn.Length > 0) sReturn += ",";
sReturn += DatMonth.ToShortDateString();
}
DatMonth = DatMonth.AddDays(1.0);
}
return sReturn;
}
[HttpGet]
public ActionResult TradeUKKPISearchesData()
{
string allSundaysInMonth = GetDatesOfSundays(System.DateTime.Now);
//var reportData = _reportingService.GetTradeUKKPISearches();
//return View(reportData);
}
the problem lies with my type string for allSundaysInMonth and is also empty ofcourse. The sReturn is of type string but then again I pass a date(I know :) ) but what type should allSundaysInMonth be? sReturn does have the correct dates in...I need to display these dates in a dropdown in the view of the controller so the user can select any of the sundays for which he/she needs to run a report for.
thanks
How about
private IEnumerable<DateTime> GetDatesOfSundays(DateTime DatMonth)
{
int iDayOffset = DatMonth.Day - 1;
DatMonth = DatMonth.AddDays(System.Convert.ToDouble(-DatMonth.Day + 1));
DateTime DatMonth2 =
DatMonth.AddMonths(1).AddDays(System.Convert.ToDouble(-1));
while (DatMonth < DatMonth2)
{
if (DatMonth.DayOfWeek == System.DayOfWeek.Sunday)
{
yield return DatMonth;
}
DatMonth = DatMonth.AddDays(1.0);
}
}
I would be tempted to rewrite your function as an extension somthing like this
public static IEnumerable<Datetime> DaysOfMonth(
this DateTime any,
DayOfWeek day)
{
// start at first of month
var candidate = new DateTime(any.Year, any.Month, 1);
var offset = (int)day - (int)candidate.DayOfWeek;
if (offset < 0)
{
offset += 7
}
candidate = candidate.AddDays(offset);
while (cadidate.Month == any.Month)
{
yield return candidate;
candidate = candidate.AddDays(7.0)
}
}
Then you could use it like this
var allSundaysInMonth = DateTime.Now.DaysOfMonth(DayOfWeek.Sunday);
If you want to convert an IEnumerable<DateTime> to a string you could do this,
var listOfDates = string.Join<DateTime>(", ", allSundaysInMonth);
using this string.Join overload
If you really want the days as a DateTime[] you could do this (but there is no need)
DateTime[] allSundaysInMonth = GetDatesOfSundays(DateTime.Now).ToArray();
or for my extension example
var allSundaysInMonth = DateTime.Now.DaysOfMonth(DayOfWeek.Sunday).ToArray();
You can go for DateTime[] or IEnumerable<DateTime>.
Your method signature should be
private IEnumerable<DateTime> GetDatesOfSundays(DateTime DatMonth)
or
private DateTime[] GetDatesOfSundays(DateTime DatMonth)
If you havn't worked with IEnumerable go for this
private DateTime[] GetDatesOfSundays(DateTime DatMonth)
{
List<DateTime> lst = new List<DateTime>();
DatMonth = DatMonth.AddDays(-DatMonth.Day + 1);
DateTime DatMonth2 = DatMonth.AddMonths(1).AddDays(System.Convert.ToDouble(-1));
while (DatMonth < DatMonth2)
{
if (DatMonth.DayOfWeek == System.DayOfWeek.Sunday)
{
lst.Add(DatMonth);
DatMonth = DatMonth.AddDays(7);
continue;
}
DatMonth = DatMonth.AddDays(1);
}
return lst.ToArray();
}
and call it as
DateTime[] allSundaysInMonth = GetDatesOfSundays(System.DateTime.Now);