Develop Reference

How can I tell DateTime in C# to set the date to a certain language?

private DateTime mDate = DateTime.Now;
mDate.ToLongDateString();
My location is Germany so it displays for example Samstag as Saturday.

You can set the current culture before calling ToLongDateString as shown in the help for that call at: https://learn.microsoft.com/en-us/dotnet/api/system.datetime.tolongdatestring?view=net-6.0
Or, you can pass an appropriate format string to ToString and provide format information as described here: https://learn.microsoft.com/en-us/dotnet/api/system.datetime.tostring?view=net-6.0#System_DateTime_ToString_System_String_System_IFormatProvider_
For example if you wanted a long date string in French (from France), you could:
var culture = CultureInfo.GetCultureInfo("fr-FR");
var dateString = DateTime.Now.ToString("D", culture);
Result: "samedi 18 décembre 2021"

Convert(change) current DateTime as per culture in c#

if (!IsPostBack && !Page.IsCallback)
{
double OffsetHrs = GetTimeZoneOffsetFromCookie();
string dateFormat = ServiceManager.LocalizationService.GetString("AppHeaderTop", "DateFormat", "g");
CultureSelected CultureSelected = GetCultureSelected();
ASPxLabelCurrentTime.Text = DateTime.Now.ToUniversalTime().AddHours(-OffsetHrs).ToString(dateFormat);
if (CultureSelected.CultureCode != "en-US")
{
DateTimeFormatInfo usDtfi = new CultureInfo("en-US", false).DateTimeFormat;
DateTimeFormatInfo currentDtfi = new CultureInfo(CultureSelected.CultureCode, false).DateTimeFormat;
ASPxLabelCurrentTime.Text = Convert.ToDateTime(ASPxLabelCurrentTime.Text, usDtfi).ToString(currentDtfi.ShortDatePattern); //what can i Use here ?
}
Let say Output of ASPxLabelCurrentTime.Text
for en-US culture is 11/2/2015 4:14 PM (70)
If I select specific culture I want this datetime 11/2/2015 4:14 PM (70) to appear in that specific culture format.

Your question seems unclear but I try to give a shot.
First of all, what is this (70) exactly? Where is this came from? en-US culture can't parse this string without using it in a string literal delimiter with ParseExact or TryParseExact methods. On the other hand, since you assing ASPxLabelCurrentTime.Text the result of the DateTime.Now.ToUniversalTime().AddHours(-OffsetHrs).ToString(dateFormat) code, I don't believe this (70) part is really an issue on this question.
Second, If I understand clearly, the problem seems the usage of DateTime.ToString(string) method.
ASPxLabelCurrentTime.Text = Convert.ToDateTime(ASPxLabelCurrentTime.Text, usDtfi)
.ToString(currentDtfi.ShortDatePattern);
// ^^^ Problem seems here
Okey let's say you successfully parse this ASPxLabelCurrentTime.Text with usDtfi culture (which is en-US), but with this .ToString(string) method, you are not using currentDtfi settings actually, you are using CurrentCulture settings when you generate formatted string representation of your DateTime.
From DateTime.ToString(String) doc;
Converts the value of the current DateTime object to its equivalent
string representation using the specified format and the formatting
conventions of the current culture.
Since we don't know what GetCultureSelected method returns exactly, it may or may not be the same culture with currentDtfi.
I strongly suspect, you can solve this problem to using that culture as a second parameter in ToString method as;
ASPxLabelCurrentTime.Text = Convert.ToDateTime(ASPxLabelCurrentTime.Text, usDtfi)
.ToString(currentDtfi.ShortDatePattern, currentDtfi);
IF this (70) is really part of on your string, you need to ParseExact or TryParseExact methods to supply exact format of it.
string s = "11/2/2015 4:14 PM (70)";
DateTime dt;
if(DateTime.TryParseExact(s, "MM/d/yyyy h:mm tt '(70)'", CultureInfo.GetCultureInfo("en-US"),
DateTimeStyles.None, out dt))
{
ASPxLabelCurrentTime.Text = dt.ToString(currentDtfi.ShortDatePattern, currentDtfi);
}

Storing date time in culture neutral format + C#

I accept date info from the user, via date picker. I need to store them in a culture neutral way. The problem I am facing is, if I store the date as per en-US format (based on calendar settings), namely 11/20/1990 it will fail to parse when the culture is en-GB.
And vice versa happens when culture is en-US, date stored as per UK format, dd/mm/yyyy refuses to parse. How do I store date info in a culture neutral way in a file so that, I get the date to work in both locations?
DateTime.TryParse(userEnteredValue, out result);
result.ToShortDateString(); //this is what I am doing
tried this code for invariant culture
string input = "20/10/1983";
DateTime userInput;
bool result = DateTime.TryParse(input, out userInput);
string invariantCulture = userInput.Date.ToString(CultureInfo.InvariantCulture);
DateTime storedValue;
result = DateTime.TryParse(invariantCulture, out storedValue);
tried this code with en-GB calendar settings, second statement DateTime.TryParse fails infact.

#Soner Gönül's answer is spot on if you are saving the dates to a database. However, you mention that you are looking to round-trip a DateTime to and from a file.
As the file is presumably a text file you'll need to write the DateTime in a culture neutral manner. You can do this by using the "O" format specified on the DateTime.ToString method. This will output a string representation that complies with ISO 8601. The resultant string can be parsed using DateTime.Parse without the need for culture information.
As an example:
string filename = #"c:\temp\test.txt";
string usDateString = "11/18/2014 12:32"; // MM/dd/yyyy
string ukDateString = "18/11/2014 12:33"; // dd/MM/yyyy
//I'm mimicking you getting the DateTime from the user here
//I'm assuming when you receive the date(s) from the front
//end you'll know the culture - if not then all bets are off.
DateTime usDate =
DateTime.Parse(usDateString, CultureInfo.GetCultureInfo("en-US"));
DateTime ukDate =
DateTime.Parse(ukDateString, CultureInfo.GetCultureInfo("en-GB"));
//write the dates to a file using the "o" specifier
File.AppendAllText(filename, usDate.ToString("o") + Environment.NewLine);
File.AppendAllText(filename, ukDate.ToString("o") + Environment.NewLine);
//read them back in as strings
string[] contents = File.ReadAllLines(filename);
foreach (var date in contents)
{
//prove we can parse them as dates.
Console.WriteLine(DateTime.Parse(date).ToString());
}
This creates a file with the contents:
2014-11-18T12:32:00.0000000
2014-11-18T12:33:00.0000000
and on my system (in the UK) it prints:
18/11/2014 12:32:00
18/11/2014 12:33:00

if I store the date as per en-US format...
Please stop! Looks like you try to save your DateTime values with their string representations.
A DateTime doesn't have any implicit format. It has just date and time values. String representations of them can have a format. Generate your insert queries and pass your DateTime values directly with parameterized way.
Please read;
Bad habits to kick : choosing the wrong data type
If you want to get string representations of your DateTime values with specific format, you can always use DateTime.ToString() method and it's overloads.
Your en-GB culture can parse MM.dd.yyyy (since you use / format specifier which replaces itself supplied culture DateSeparator) and en-US culture can parse MM/dd/yyyy as well.
But since you use .ToShortDateString() method, this represents your datetime based your CurrentCulture settings. As a solution, you can set this property which culture you want and ToShortDateString works based on it.
result = DateTime.TryParse(invariantCulture, out storedValue);
tried this code with en-UK calendar settings, second statement
DateTime.TryParse fails infact.
Because this DateTime.TryParse uses your CurrentCulture and since your invariantCulture variable is 10/20/1983 00:00:00, that means this is not a standard date and time format for your CurrentCulture.
There is no such a culture as en-UK by the way.
10/20/1983 00:00:00 is MM/dd/yyyy HH:mm:ss format. But en-GB culture doesn't have this format as a standard date and time format, that's why your method returns false.
As an alternative, you can use custom format strings like;
string s = "10/20/1983 00:00:00";
string format = "MM/dd/yyyy HH:mm:ss";
DateTime dt;
if (DateTime.TryParseExact(s, format, CultureInfo.GetCultureInfo("en-GB"),
DateTimeStyles.None, out dt))
{
Console.WriteLine(dt);
}

I bumped into this question and figured I'd bring in some other way nobody has mentioned yet:
DateTime.ToBinary() for serializing and DateTime.FromBinary(Int64) for deserialization.
What these do is the following:
ToBinary() returns a long which can be easily stored in a culture invariant way.
FromBinary(Int64) will return a DateTime object from the long parameter supplied.
(They even take the date time Kind property into consideration).
And here's some code to go with it:
DateTime d1l = DateTime.Now;
long dl = d1l.ToBinary();
DateTime d2l = DateTime.FromBinary(dl);
DateTime d1u = DateTime.UtcNow;
long du = d1u.ToBinary();
DateTime d2u = DateTime.FromBinary(du);
Console.WriteLine("Local test passed: " + (d1l == d2l).ToString());
Console.WriteLine("d2l kind: " + d2l.Kind.ToString());
Console.WriteLine("Utc test passed: " + (d1u == d2u).ToString());
Console.WriteLine("d2u kind: " + d2u.Kind.ToString());
And the console output:
Local test passed: True
d2l kind: Local
Utc test passed: True
d2u kind: Utc
I find this to be pretty neat!

String s = "24. 11. 2001";
d = DateTime.Parse(s, CultureInfo.CreateSpecificCulture("sk-SK"));
en-AU (English Austrailia): 24/11/2001
en-IA (English India): 24-11-2001
en-ZA (English South Africa): 2001/11/24
en-US (English United States): 11/24/2001
i suspect you prefer English (India) (en-IA).
But if you really can't decide what culture to use when converting dates to strings and vice-versa, and the dates are never meant to be shown to a user, then you can use the Invariant Culture:
String s = "11/24/2001" //invariant culture formatted date
d = DateTime.Parse(s, CultureInfo.InvariantCulture); //parse invariant culture date
s = d.ToString(CultureInfo.InvariantCulture); //convert to invariant culture string

I tried to figure out a solution via this approach, please let me know if its correct.
The code which I use is below.
For Saving date time I use ticks as below.
DateTime userInput;
bool result = DateTime.TryParse(this.dpSave.Text, out userInput);
if (result)
{
long ticks = userInput.Ticks;
System.IO.File.WriteAllText(#"D:\folder\Ticks.txt", ticks.ToString());
}
else
{
MessageBox.Show("Date time parse failed");
}
For loading it back, I use
if (System.IO.File.Exists(#"D:\folder\Ticks.txt"))
{
string contents = System.IO.File.ReadAllText(#"D:\Sandeep\Ticks.txt");
long ticks;
if (long.TryParse(contents, out ticks))
{
DateTime storedDateTime = new DateTime(ticks);
MessageBox.Show("Stored Date" + storedDateTime.ToShortDateString());
}
else
{
MessageBox.Show("Unable to obtain stored dates");
}
}
this seems to work, provided, I save using en-US culture and load using en-GB culture.
please let me know if this is the right approach!

a) Exchange data shall always be stored culture invariant (xml etc)
b)You've gotta to be careful with the terminology.
What you exactly mean is culture INVARIANT (and not 'culture neutral').
There are three types of cultures:
1) invariant
2) culture neutral (e.g. "en")
3) culture specific (e.g "en-US")

public DateTime getdate3()
{
CultureInfo Invc = CultureInfo.InvariantCulture; //culture
string cul = Thread.CurrentThread.CurrentCulture.Name;
CultureInfo us = new CultureInfo(cul);
string shortUsDateFormatString = us.DateTimeFormat.ShortDatePattern;//pattern
DateTime dt = Convert.ToDateTime(DateTime.Now);
TimeZoneInfo myZone = TimeZoneInfo.FindSystemTimeZoneById("India Standard Time"); //india zone
DateTime dateindia = TimeZoneInfo.ConvertTime(dt, myZone);
string dt1 = Convert.ToDateTime(dateindia).ToString(shortUsDateFormatString); //string format
}

.NET - Canadian DateTime Format Bug

I currently have an application that needs to support multiple cultures. A date string is being passed in and is being parsed to a DateTime object. To allow for multiple cultures I am first setting the thread's culture and UICulture.
Here is an example of my code as it is:
First I set the culture for this thread. This is passed in on the URL (ex. en-us, en-ca, fr-ca):
CultureInfo ci = new CultureInfo(culture, false);
Thread.CurrentThread.CurrentUICulture = ci;
Thread.CurrentThread.CurrentCulture = ci;
I then take a date string that is also passed in on the URL and convert it to a DateTime. Depending on the culture the date will be passed in as mm/dd/yyyy or dd/mm/yyyy.
I parse the date strings with the following code:
DateTime DateTimeObject;
bool validDate = DateTime.TryParse(DateStringFromURL, Thread.CurrentThread.CurrentCulture, DateTimeStyles.None, out DateTimeObject);
The TryParse works for most cultures and out comes a valid datetime object. A problem arises with en-ca and fr-ca though. If the wrong format is passed in, the datestring does not parse correctly.
The following shows which format .NET seems to expect for each culture:
dd/MM/yyyy MM/dd/yyyy
EN-CA Valid Invalid
FR-CA Invalid Valid
EDIT:
To be more exact here are the examples causing me problems:
For EN-CA:
DateTime.Parse("26/08/2014") //VALID
DateTime.Parse("08/26/2014") //EXCEPTION THROWN
For FR-CA:
DateTime.Parse("26/08/2014") //EXCEPTION THROWN
DateTime.Parse("08/26/2014") //VALID
This is backwards from how other systems treat this culture's date formatting.
Why are the formats seemingly backwards?
Is this a bug with .NET 4.5?
Any and all help would be appreciated, thanks.
NOTE: .NET Version 4.5

You should probably look into Invariant culture. That is what you should use for your URL passing. You can use the local culture for display purposes on the client.
Typically, whenever you are storing data (for example, in a database or file ) it is best to use the Invariant culture. When displaying data you can use the local culture. When passing data around, you want to use Invariant culture.
Read more here.

I believe your assumptions are wrong. This console application:
static void Main(string[] args)
{
var enca = new CultureInfo("en-ca", false);
var frca = new CultureInfo("fr-ca", false);
Console.WriteLine("enca dd/MM/yyyy: " + ParseDate("26/08/2014", enca));
Console.WriteLine("enca MM/dd/yyyy: " + ParseDate("08/26/2014", enca));
Console.WriteLine("frca dd/MM/yyyy: " + ParseDate("26/08/2014", frca));
Console.WriteLine("frca MM/dd/yyyy: " + ParseDate("08/26/2014", frca));
Console.ReadKey();
}
static bool ParseDate(string date, CultureInfo culture)
{
try
{
DateTime.Parse(date, culture);
return true;
}
catch
{
return false;
}
}
Has output:
enca dd/MM/yyyy: False
enca MM/dd/yyyy: True
frca dd/MM/yyyy: False
frca MM/dd/yyyy: True

There is definitely a bug in data parsing for Canadian culture. If you try following having CurrentCulture = "en-CA":
DateTime.ParseExact("2014/09/20", "yyyy/MM/dd", Thread.CurrentThread.CurrentCulture)
you'll get following exception:
A first chance exception of type 'System.FormatException' occurred in mscorlib.dll
works fine if you replace / with something else, like - or with InvariantCulture.

convert DateTime to string according to customCultureInfo in G((combination of date and Time) format

I have changed my system date format to Faeroese.
I want to convert DateTime to String according to customCulture with G format (combination of date and Time)
check the below code.
namespace TestDateConvertion
{
class Program
{
static void Main(string[] args)
{
object value = new DateTime(2003,12,23,6,22,30);
DateTime dateTimeValue = (DateTime)value;
CultureInfo customCulture = MySettings.getCustomCulture();
//for getting custom culture in my app
//in custom culture i have changed shortDateFormat according to the user preference.
//value in shortDateFormat = dd/MM/yyyy
string result = string.Format(customCulture, "{0:G}", result);
Console.WriteLine(result);
Console.ReadLine();
}
}
}
but i get the output with sepertators according to system DateTime not with users given format in customCulture,
i even dont find any method overloaded in string.Format() or DateTime.ToString() to do this.
If i pass CultureInfo.InvariantCulture then i cant get output in G format.

try this:
DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
Console.WriteLine(date1.ToString("G", DateTimeFormatInfo.InvariantInfo));
// Displays 04/10/2008 06:30:00
Console.WriteLine(date1.ToString("G", CultureInfo.CreateSpecificCulture("en-us")));
// Displays 4/10/2008 6:30:00 AM
Console.WriteLine(date1.ToString("G", CultureInfo.CreateSpecificCulture("nl-BE")));

According to Standard Date and Time Format Strings "G" uses short date format (as you claim to specify). So most likely reason of using local culture separator is covered in The "/" Custom Format Specifier portion of ""Custom Date and Time Format Strings".
Since your "short date format" is "dd/MM/yyyy" than instead of "/" it will use corresponding separator from the culture info (which you are likely picking from default culture).
Escaping with \ is covered in the Using the escape character portion of the same "Custom Date and Time Format Strings" article.
So you want your shortDateFormat = #"dd\/MM\/yyyy" or properly specify DateTimeSeparator in corresponding part of your custom CultureInfo.