relevant loop and leap year c# - c#

I am going to say in advance, that I am a beginner in programming and this question might seem quite irrelevant. However, I truly wonder how to proceed in this situation.
This is my code:
string startdate;
Console.WriteLine("Please, type in your birthdate (dd-mm-yyyy)");
startdate = Console.ReadLine();
DateTime bday = DateTime.Parse(startdate);
// prob 1.
DateTime now = DateTime.Now;
TimeSpan ts1 = now.Subtract(bday);
DateTime dt = new DateTime(0001, 01, 01);
TimeSpan ts2 = new TimeSpan(365, 0, 0, 0);
//prob2.
TimeSpan ts3 = new TimeSpan(3650, 0, 0, 0);
dt = dt + ts1 - ts2;
Console.WriteLine("Your current age is:{0}", dt.ToString("yy"));
dt = dt + ts3;
Console.WriteLine("Your Age after 10 years will be:{0}", dt.ToString("yy"));
Problem 1: I would like to create a loop where if the info that is given in the console is different from dd-mm-yyyy, to repeat the whole process again.
Problem 2: I would like to see whether the next year(from the current one) is a leap year, and thus know whether ts2 should be 365 days or 366.
Thank you in advance.

Re. Problem 1:
Take a look at DateTime.TryParseExact: this allows you to specify a format, and rather than throwing an exception returns false on the input format not matching. Thus
DateTime res;
String inp;
do {
inp = Console.ReadLine("Date of birth: ");
} while (!DateTime.TryParseExact(inp, "yyyy-MM-dd", CultureInfo.CurrentCulture, DateTimeStyles.None, out res));
Re, Problem 2: See DateTime.AddYears as noted in the comments on the Q.

The Leap year problem is not really a problem thanks to the Framewrok
int daysToAdd = 0;
for(int i = 1; i <= 10; i++)
daysToAdd += (DateTime.IsLeapYear(DateTime.Today.Year + i) ? 366 : 365);
The first problem could be solved with
DateTime inputDate;
while(true)
{
Console.WriteLine("Please, type in your birthdate (dd-mm-yyyy)");
string startdate = Console.ReadLine();
if(DateTime.TryParseExact(startdate, "dd-MM-yyyy", CultureInfo.CurrentCulture, DateTimeStyles.None, out inputDate))
break;
}

Problem 1:
That can be solved using a while loop.
while(!DateTime.Parse(startdate))// The "!" is for NOT
{
Console.WriteLine("Incorrect format please type your birthday again(dd-mm-yyyy)");
startdate = Console.ReadLine();
}
However this brings up another problem DateTime.Parse will throw an error when the string is incorrect.(http://msdn.microsoft.com/en-us/library/1k1skd40%28v=vs.110%29.aspx)
In order to solve this you need to do use a try catch clause in order to "catch" the error.
See more details here(http://msdn.microsoft.com/en-us/library/0yd65esw.aspx)
Therefore the code will look like this:
bool isCorrectTime = false;
while(!isCorrectTime) // The "!" is for NOT
{
try
{
Console.WriteLine("Incorrect format please type your birthday again(dd-mm-yyyy)");
startdate = Console.ReadLine();
isCorrectTime = true; //If we are here that means that parsing the DateTime
// did not throw errors and therefore your time is correct!
}
catch
{
//We leave the catch clause empty as it is not needed in this scenario
}
}
For problem 2 see Steve's answer.

Related

How to convert a string to DateTime in a TextBox of a gridview [duplicate]

How do you convert a string such as 2009-05-08 14:40:52,531 into a DateTime?
Since you are handling 24-hour based time and you have a comma separating the seconds fraction, I recommend that you specify a custom format:
DateTime myDate = DateTime.ParseExact("2009-05-08 14:40:52,531", "yyyy-MM-dd HH:mm:ss,fff",
System.Globalization.CultureInfo.InvariantCulture);
You have basically two options for this. DateTime.Parse() and DateTime.ParseExact().
The first is very forgiving in terms of syntax and will parse dates in many different formats. It is good for user input which may come in different formats.
ParseExact will allow you to specify the exact format of your date string to use for parsing. It is good to use this if your string is always in the same format. This way, you can easily detect any deviations from the expected data.
You can parse user input like this:
DateTime enteredDate = DateTime.Parse(enteredString);
If you have a specific format for the string, you should use the other method:
DateTime loadedDate = DateTime.ParseExact(loadedString, "d", null);
"d" stands for the short date pattern (see MSDN for more info) and null specifies that the current culture should be used for parsing the string.
try this
DateTime myDate = DateTime.Parse(dateString);
a better way would be this:
DateTime myDate;
if (!DateTime.TryParse(dateString, out myDate))
{
// handle parse failure
}
Use DateTime.Parse(string):
DateTime dateTime = DateTime.Parse(dateTimeStr);
Nobody seems to implemented an extension method. With the help of #CMS's answer:
Working and improved full source example is here: Gist Link
namespace ExtensionMethods {
using System;
using System.Globalization;
public static class DateTimeExtensions {
public static DateTime ToDateTime(this string s,
string format = "ddMMyyyy", string cultureString = "tr-TR") {
try {
var r = DateTime.ParseExact(
s: s,
format: format,
provider: CultureInfo.GetCultureInfo(cultureString));
return r;
} catch (FormatException) {
throw;
} catch (CultureNotFoundException) {
throw; // Given Culture is not supported culture
}
}
public static DateTime ToDateTime(this string s,
string format, CultureInfo culture) {
try {
var r = DateTime.ParseExact(s: s, format: format,
provider: culture);
return r;
} catch (FormatException) {
throw;
} catch (CultureNotFoundException) {
throw; // Given Culture is not supported culture
}
}
}
}
namespace SO {
using ExtensionMethods;
using System;
using System.Globalization;
class Program {
static void Main(string[] args) {
var mydate = "29021996";
var date = mydate.ToDateTime(format: "ddMMyyyy"); // {29.02.1996 00:00:00}
mydate = "2016 3";
date = mydate.ToDateTime("yyyy M"); // {01.03.2016 00:00:00}
mydate = "2016 12";
date = mydate.ToDateTime("yyyy d"); // {12.01.2016 00:00:00}
mydate = "2016/31/05 13:33";
date = mydate.ToDateTime("yyyy/d/M HH:mm"); // {31.05.2016 13:33:00}
mydate = "2016/31 Ocak";
date = mydate.ToDateTime("yyyy/d MMMM"); // {31.01.2016 00:00:00}
mydate = "2016/31 January";
date = mydate.ToDateTime("yyyy/d MMMM", cultureString: "en-US");
// {31.01.2016 00:00:00}
mydate = "11/شعبان/1437";
date = mydate.ToDateTime(
culture: CultureInfo.GetCultureInfo("ar-SA"),
format: "dd/MMMM/yyyy");
// Weird :) I supposed dd/yyyy/MMMM but that did not work !?$^&*
System.Diagnostics.Debug.Assert(
date.Equals(new DateTime(year: 2016, month: 5, day: 18)));
}
}
}
I tried various ways. What worked for me was this:
Convert.ToDateTime(data, CultureInfo.InvariantCulture);
data for me was times like this 9/24/2017 9:31:34 AM
Try the below, where strDate is your date in 'MM/dd/yyyy' format
var date = DateTime.Parse(strDate,new CultureInfo("en-US", true))
Convert.ToDateTime or DateTime.Parse
DateTime.Parse
Syntax:
DateTime.Parse(String value)
DateTime.Parse(String value, IFormatProvider provider)
DateTime.Parse(String value, IFormatProvider provider, DateTypeStyles styles)
Example:
string value = "1 January 2019";
CultureInfo provider = new CultureInfo("en-GB");
DateTime.Parse(value, provider, DateTimeStyles.NoCurrentDateDefault););
Value: string representation of date and time.
Provider: object which provides culture specific info.
Styles: formatting options that customize string parsing for some date and time parsing methods. For instance, AllowWhiteSpaces is a value which helps to ignore all spaces present in string while it parse.
It's also worth remembering DateTime is an object that is stored as number internally in the framework, Format only applies to it when you convert it back to string.
Parsing converting a string to the internal number type.
Formatting converting the internal numeric value to a readable
string.
I recently had an issue where I was trying to convert a DateTime to pass to Linq what I hadn't realised at the time was format is irrelevant when passing DateTime to a Linq Query.
DateTime SearchDate = DateTime.Parse(searchDate);
applicationsUsages = applicationsUsages.Where(x => DbFunctions.TruncateTime(x.dateApplicationSelected) == SearchDate.Date);
Full DateTime Documentation
string input;
DateTime db;
Console.WriteLine("Enter Date in this Format(YYYY-MM-DD): ");
input = Console.ReadLine();
db = Convert.ToDateTime(input);
//////// this methods convert string value to datetime
///////// in order to print date
Console.WriteLine("{0}-{1}-{2}",db.Year,db.Month,db.Day);
You could also use DateTime.TryParseExact() as below if you are unsure of the input value.
DateTime outputDateTimeValue;
if (DateTime.TryParseExact("2009-05-08 14:40:52,531", "yyyy-MM-dd HH:mm:ss,fff", System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out outputDateTimeValue))
{
return outputDateTimeValue;
}
else
{
// Handle the fact that parse did not succeed
}
I just found an elegant way:
Convert.ChangeType("2020-12-31", typeof(DateTime));
Convert.ChangeType("2020/12/31", typeof(DateTime));
Convert.ChangeType("2020-01-01 16:00:30", typeof(DateTime));
Convert.ChangeType("2020/12/31 16:00:30", typeof(DateTime), System.Globalization.CultureInfo.GetCultureInfo("en-GB"));
Convert.ChangeType("11/شعبان/1437", typeof(DateTime), System.Globalization.CultureInfo.GetCultureInfo("ar-SA"));
Convert.ChangeType("2020-02-11T16:54:51.466+03:00", typeof(DateTime)); // format: "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffzzz"
Put this code in a static class> public static class ClassName{ }
public static DateTime ToDateTime(this string datetime, char dateSpliter = '-', char timeSpliter = ':', char millisecondSpliter = ',')
{
try
{
datetime = datetime.Trim();
datetime = datetime.Replace(" ", " ");
string[] body = datetime.Split(' ');
string[] date = body[0].Split(dateSpliter);
int year = date[0].ToInt();
int month = date[1].ToInt();
int day = date[2].ToInt();
int hour = 0, minute = 0, second = 0, millisecond = 0;
if (body.Length == 2)
{
string[] tpart = body[1].Split(millisecondSpliter);
string[] time = tpart[0].Split(timeSpliter);
hour = time[0].ToInt();
minute = time[1].ToInt();
if (time.Length == 3) second = time[2].ToInt();
if (tpart.Length == 2) millisecond = tpart[1].ToInt();
}
return new DateTime(year, month, day, hour, minute, second, millisecond);
}
catch
{
return new DateTime();
}
}
In this way, you can use
string datetime = "2009-05-08 14:40:52,531";
DateTime dt0 = datetime.TToDateTime();
DateTime dt1 = "2009-05-08 14:40:52,531".ToDateTime();
DateTime dt5 = "2009-05-08".ToDateTime();
DateTime dt2 = "2009/05/08 14:40:52".ToDateTime('/');
DateTime dt3 = "2009/05/08 14.40".ToDateTime('/', '.');
DateTime dt4 = "2009-05-08 14:40-531".ToDateTime('-', ':', '-');
String now = DateTime.Now.ToString("YYYY-MM-DD HH:MI:SS");//make it datetime
DateTime.Parse(now);
this one gives you
2019-08-17 11:14:49.000
Different cultures in the world write date strings in different ways. For example, in the US 01/20/2008 is January 20th, 2008. In France this will throw an InvalidFormatException. This is because France reads date-times as Day/Month/Year, and in the US it is Month/Day/Year.
Consequently, a string like 20/01/2008 will parse to January 20th, 2008 in France, and then throw an InvalidFormatException in the US.
To determine your current culture settings, you can use System.Globalization.CultureInfo.CurrentCulture.
string dateTime = "01/08/2008 14:50:50.42";
DateTime dt = Convert.ToDateTime(dateTime);
Console.WriteLine("Year: {0}, Month: {1}, Day: {2}, Hour: {3}, Minute: {4}, Second: {5}, Millisecond: {6}",
dt.Year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second, dt.Millisecond);
This worked for me:
CultureInfo provider = CultureInfo.InvariantCulture;
DateTime dt = DateTime.ParseExact("2009-05-08 14:40:52,531","yyyy-MM-dd HH:mm:ss,fff", provider);
Do you want it fast?
Let's say you have a date with format yyMMdd.
The fastest way to convert it that I found is:
var d = new DateTime(
(s[0] - '0') * 10 + s[1] - '0' + 2000,
(s[2] - '0') * 10 + s[3] - '0',
(s[4] - '0') * 10 + s[5] - '0')
Just, choose the indexes according to your date format of choice. If you need speed probably you don't mind the 'non-generic' way of the function.
This method takes about 10% of the time required by:
var d = DateTime.ParseExact(s, "yyMMdd", System.Globalization.CultureInfo.InvariantCulture);

How to add a century prefix to a birth date?

Trying to figure out how to add a century prefix (19 or 20) to a birth date. Does anyone see how to write this in a better way?
public string GetCenturyPrefix(string socSecNo)
{
string prefix = string.Empty;
try
{
var currentDate = DateTime.Now;
var birthDayTemp = socSecNo.Substring(0, 6);
var yy = birthDayTemp.Substring(0, 2);
var mm = birthDayTemp.Substring(2, 2);
var dd = birthDayTemp.Substring(4, 2);
birthDayTemp = yy + "-" + mm + "-" + dd;
var birthDay = Convert.ToDateTime(birthDayTemp);
var totalDays = currentDate - birthDay;
var age = totalDays.TotalDays / 365;
var yearsAfter2000 = Convert.ToInt32(currentDate.Year.ToString().Substring(2, 2));
if (age > yearsAfter2000)
{
prefix = "19";
}
else
{
prefix = "20";
}
}
catch (Exception)
{
}
return prefix;
}
Don't use Substring to parse a string value into a DateTime. .Net has very robust methods created for you to do this conversion.
Here I'm using DateTime.TryParseExact(), which lets me specify the exact format I expect dates values to be provided in. The method returns true or false indicating if the value is in that supplied format. No need to use exceptions to control logic flow.
public string GetCenturyPrefix(string socSecNo)
{
// Check if you're able to parse the incoming value
// in the format "yyMMdd".
if (!DateTime.TryParseExact(socSecNo, "yyMMdd", CultureInfo.InvariantCulture,
DateTimeStyles.None, out DateTime parsedDateTime))
{
// Do something if the input can't be parsed in that format.
// In this example I'm throwing an exception, but you can also
// return an empty string.
throw new Exception("Not valid date format");
}
// Extract only the Year portion as a 4 digit string,
// and return the first 2 characters.
return parsedDateTime.ToString("yyyy").Substring(0, 2);
}
You can do it like (year/100)+1 but put {0:n0} format to your .ToString("{0:n0}") this could be the logic and for the if else it can stay like that. This should be working for any century as I tried on calculator.

How to get the day value out of a textbox in C#?

For example, if the textbox contains 11/11/2016 OR 01/05/2016
How to get the day value only? example. 11 OR 01
One way is to parse the string in the TextBox to DateTime using an exact format. Then using the DateTime object, you can extract the Day Property:
DateTime date;
bool success = DateTime.TryParseExact(textBoxDate.Text, "dd/MM/yyyy",
CultureInfo.CurrentCulture,
DateTimeStyles.AssumeLocal, out date);
int day;
if(success)
{
day = date.Day; // 1
// or string stringDay = date.ToString("dd"); to get 01
}
else
{
// handle error
}
Another way that I don't prefer (Not 100% safe input validation) is to use String.Split like this:
string strDay = textBoxDate.Text.Split('/').FirstOrDefault();
int day;
if(Int32.TryParse(strDay, out day))
{
// success
}
else
{
// Handle Error
}
string myString = textbox1.text;
DateTime day = DateTime.ParseExact(myString, "dd/MM/yyyy", CultureInfo.InvariantCulture);
int day = birthday.Day;

Getting the first and last day of a month, using a given DateTime object

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)));

c# months and years between given dates

I try to popup a msgbox that shows the months and years of the given dates for example
my input is:
7/2012 and 2/2013
and the output should be:
7/2012,8/2012,9/2012,10/2012,11/2012,12/2012,1/2013,2/2013
I wrote:
string datePart1;
string datePart2;
string[] date1 = new string[] { "" };
string[] date2 = new string[] { "" };
private void button1_Click(object sender, EventArgs e)
{
DateTime endDate = new DateTime(2013, 2, 1); // i will be having the date time as a variable from a textbox
DateTime begDate = new DateTime(2012, 7, 1); // i will be having the date time as a variable from a text box
int year, month;
if (endDate.Month - begDate.Month < 0)
{
month = (endDate.Month - begDate.Month) + 12;
endDate = new DateTime(endDate.Year - 1, endDate.Month, endDate.Day);
}
else
month = endDate.Month - begDate.Month;
year = endDate.Year - begDate.Year;
The above code calculates the time difference, but my attempts at outputting haven't worked.
Here's a sample to get you started.
It provides a handy MonthsInRange() method which returns a sequence of all the months in the specified range. You can then format the returned dates using "M\\/yyyy" (see below) to output the required format. (Note: That's not a letter V, it's a backslash followed by a forward slash!)
See Custom Date and Time Format Strings for an explanation of the format string.
using System;
using System.Collections.Generic;
namespace Demo
{
public static class Program
{
static void Main(string[] args)
{
DateTime endDate = new DateTime(2013, 2, 1);
DateTime begDate = new DateTime(2012, 7, 1);
foreach (DateTime date in MonthsInRange(begDate, endDate))
{
Console.WriteLine(date.ToString("M\\/yyyy"));
}
}
public static IEnumerable<DateTime> MonthsInRange(DateTime start, DateTime end)
{
for (DateTime date = start; date <= end; date = date.AddMonths(1))
{
yield return date;
}
}
}
}
Why "M\\/yyyy" and not just "M/yyyy"?
This is because the "/" character in a DateTime format string will be interpreted as the "date separator", not a literal "/". In some locales, this will come out as "." and not "/".
To fix this, we need to escape it with a "\" character. However, we can't just use a single "\" because C# itself will interpret that as an escape character, and will use it to escape the following character. The C# escape sequence for a literal "\" is "\\", which is why we have to put "\\/" and not just "\/".
Alternatively you can turn of escaping of "\" characters by prefixing the string with an # character, like so:
#"M/yyyy"
You can use whichever you prefer.
Since you're not guaranteed to have dates with the same day, you can use this code which creates new dates that only consider the first of the month.
static IEnumerable<string> InclusiveMonths(DateTime start, DateTime end)
{
// copies to ensure the same day.
var startMonth = new DateTime(start.Year, start.Month, 1);
var endMonth = new DateTime(end.Year, end.Month, 1);
for (var current = startMonth; current <= endMonth; current = current.AddMonths(1))
yield return current.ToString("M/yyyy");
}
// usage
foreach (var mmyyyy in InclusiveMonths(begDate, endDate))
{
Console.WriteLine(mmyyyy);
}
var allMonths = string.Join(", ", InclusiveMonths(begDate, endDate));
Look into using the TimeSpan structure, it'll help you achieve your goal a lot faster.
http://msdn.microsoft.com/en-us/library/system.timespan.aspx
You may use
TimeSpan dateDifference = endDate - begDate;
year = dateDifference.Days / 365;
month = dateDifference.Days / 30;
Edit:
I forgot TimeSpan does not feature Year or Month, sorry :(

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