I want to convert a string to datetime format.
The thing is that the string comes in different formats.
For instance, in the code below, strDate can be "2/20/2014 1:41:57 PM" or "20/02/2014 13:44:56".
Convert.ToDateTime(strDate) executes well just for one format (the one on the user browser settings) and generates an error for the other.
How can I successfully convert the string to datetime independently of the string format?
Thanks
DateTime dt = Convert.ToDateTime(strDate);
You can use DateTime.TryParseExact or Datetime.ParseExact with multiple formats like:
string dateStr = "20/02/2014 1:41:57 PM";
string[] dateFormats = new[]
{
"d/M/yyyy h:mm:ss tt",
"M/d/yyyy h:mm:ss tt",
};
DateTime dt;
if (DateTime.TryParseExact(dateStr,
dateFormats,
CultureInfo.InvariantCulture,
DateTimeStyles.None,
out dt))
{
//valid dates for formats
}
else
{
//invalid date
}
the problem with this approach is that it would give you inconsistent results with strings like 10/02/2014 1:41:57 PM, The above code would parse it as 10th Feb 2014, not as October 2nd 2014, to avoid this you can customize your client side to return date in specific format and then parse accordingly.
you want DateTime.Parse() or DateTime.TryParse()
i.e.
DateTime dt;
if(DateTime.TryParse(stringDate, out dt)
{
//successful datetime conversion
}
if you know the string will be one of several exact formats, you can use DateTime.TryParseExact() and pass in a string array of each format (the second overload).
Related
edit: since I've had so many comments regarding utilising TryParseExact with a single format instead of an array:
I must test all of the formats within the array - the inputs can potentially be these formats, and my unit tests for these other formats actually work. I MUST use them all.
I am aware that DateTime.TryParse would match the first and not iterate further. Hence I am using TryParseExact as Microsoft shows. It should match exactly. BUT it doesn't work in this scenario.
TLDR: Given a string of the format "dd/MM/yyyy" with value "29/11/2019" DateTime.TryParseExact returns a match with the format "dd/MM/yyyy hh:mm tt" and value 29/11/2019 12:00 AM. Why?
Question: How can I ensure a string of the format "dd/MM/yyyy" returns as a match with the format "dd/MM/yyyy" instead of "dd/MM/yyyy hh:mm tt" when using TryParseExact?
The long explanation of Context;
I have the following problem. I need to parse multiple date formats from strings to datetime values. They (input strings) can appear in the following formats:
{ "dd/MM/yyyy hh:mm tt", "dd/M/yyyy hh:mm tt", "dd/MM/yyyy H:mm", "dd/MM/yyyy H:mm", "dd/MM/yyyy H:m", "dd/MM/yyyy", "dd-MM-yyyy", "d-M-yyyy", "dddd, d MMMM yyyy"};
To solve this, I wrote a string extension that parses a given input string and returns a bool success and a potential matching format.
private static readonly string[] _DateFormats = new string[] { "dd/MM/yyyy hh:mm tt", "dd/M/yyyy hh:mm tt", "dd/MM/yyyy H:mm", "dd/MM/yyyy H:mm", "dd/MM/yyyy H:m", "dd/MM/yyyy", "dd-MM-yyyy", "d-M-yyyy", "dddd, d MMMM yyyy"};
public static bool StringToDateTime(this string dateTimeString, out DateTime dateTimeValue, out string matchingFormat)
{
matchingFormat = ""; // defaults
dateTimeValue = new DateTime();
if (string.IsNullOrEmpty(dateTimeString)) return false;
foreach (string format in DateFormats)
{
matchingFormat = format;
if (DateTime.TryParseExact(dateTimeString, DateFormats, AUSCulture, DateTimeStyle, out dateTimeValue)) return true;
}
return false;
}
This returns the string input "29/11/2019 successfully" as the DateTime 29/11/2019 12:00 AM with the matching format as "dd/MM/yyyy hh:mm tt", rather than the format matching the original input 29/11/2019.
Given this issue, the only (duct-tape) solution I could think of is:
public static bool StringToDateTime(this string dateTimeString, out DateTime dateTimeValue, out string matchingFormat)
{
matchingFormat = ""; // defaults
dateTimeValue = new DateTime();
if (string.IsNullOrEmpty(dateTimeString)) return false;
foreach (string format in DateFormats)
{
matchingFormat = format;
if (DateTime.TryParseExact(dateTimeString, DateFormats, AUSCulture, DateTimeStyle, out dateTimeValue))
{
// ensure the datetime format is consistent with the dateTimeString passed to us.
if(dateTimeString.Length != matchingFormat.Length)
{
var _matchingFormat = DateFormats.First(d => d.Length == dateTimeString.Length);
matchingFormat = string.IsNullOrEmpty(_matchingFormat) ? matchingFormat : _matchingFormat;
}
return true;
}
}
return false;
}
Which works, but obviously, this has further issues (begetting the formatting of input, etc.). So I'd rather not use this.
System.DateTime cannot exist without the time component, so it's no possible to parse a date to DateTime and not the time component. It will default to the start of day e.g. 12:00 AM, which is the same result as calling dateTime.Date(). This will allow you to compare two dates without considering the time of day.
If having or storing the time element really bothers you then you can either create your own struct to store the date or consider using something like NodaTime that provides a date only struct.
Also, Dotnet 6 will introduce DateOnly and TimeOnly structs to do exactly this. You can read more about it on the MS devblogs.
You are passing the whole array of formats, so it will match any of them.
Since you are in a foreach over DateFormats, you only need to match against the current value.
So replace this line
if (DateTime.TryParseExact(dateTimeString, DateFormats, AUSCulture, DateTimeStyle, out dateTimeValue))
return true;
with this
if (DateTime.TryParseExact(dateTimeString, format, AUSCulture, DateTimeStyle, out dateTimeValue))
return true;
I have the following output in string:
24/05/15 11:40:50 AM
now I want to convert this string into -> 2015-05-24 11:40:50.000
I have tried below method but it gives me error :
String was not recognized as a valid DateTime.
DateTime.ParseExact("24/05/15 11:40:50 AM",
"yyyy-MM-dd HH:mm:ss",
CultureInfo.InvariantCulture);
From documentation;
Converts the specified string representation of a date and time to its
DateTime equivalent. The format of the string representation must
match a specified format exactly.
In your case, they are not.
First, you can parse it to DateTime with specific format and you can generate a string representation with a specific format from that DateTime. Like;
string s = "24/05/15 11:40:50 AM";
DateTime dt;
if(DateTime.TryParseExact(s, "dd/MM/yy hh:mm:ss tt", CultureInfo.InvariantCulture,
DateTimeStyles.None, out dt))
{
Console.WriteLine(dt.ToString("yyyy-MM-dd hh:mm:ss.fff"));
}
Prints;
2015-05-24 11:40:50.000
What is the right DateTime format to parse a date from string in general date format ("G") with optional time part ("d")?
I can have two types of dates:
"12/13/2012 6:30:00 PM"
"3/29/2013"
How to parse them in unified way?
Right now I'm trying to parse with "G" format and then if it not parsed with "d" format.
If your CurrentCulture supports MM/dd/yyyy h:mm:ss tt (I assume your LongTimePattern has h) and M/dd/yyyy (I assume your ShortDatePattern has M) as standard date and time format, using DateTime.TryParse(String, out DateTime) method can solve all your problems.
string s = "";
DateTime dt;
if (DateTime.TryParse(s, out dt))
{
// Your string parsed successfully.
}
If these formats doesn't standard date and time format for your CurrentCulture, using DateTime.TryParseExact(String, String[], IFormatProvider, DateTimeStyles, DateTime) overload can be the best choice because it takes formats part as a string array. That means, you can provide multiple formats and your string will be parsed with first successful match.
string s = "";
string[] formats = { "MM/dd/yyyy h:mm:ss tt", "M/dd/yyyy" };
DateTime dt;
if (DateTime.TryParseExact(s, formats, CultureInfo.CurrentCulture,
DateTimeStyles.None, out dt))
{
// Your string parsed with one of speficied format.
}
Be careful when you parse string that have "/" custom format specifier. It has a special meaning of replace me with current culture or specified culture date separator. That means if your CurrentCulture's DateSeparator property is not /, your parsing operation will fail even if your string and formats are the same format.
Just use DateTime.Parse() or if you want to do a safe parse attempt DateTime.TryParse()
DateTime dt1, dt2;
dt1 = DateTime.Parse("12/13/2012 6:30:00 PM");
dt2 = DateTime.Parse("3/29/2013");
OR
DateTime.TryParse("12/13/2012 6:30:00 PM", out dt1);
DateTime.TryParse("3/29/2013", out dt2);
You only have to use DateTime.ParseExact() or provide the format if it differs from the accepted formats that DateTime.Parse() accepts, or if you only allow one particular format.
I need to know exact date format that will perse the string 16-Aug-78 12:00:00 AM. I have tried various string like "ss-MMM-yy hh:mm:ss". Is there any way for finding it to converting to any general format. I am using CultureInfo.InvariantCulture class.
Your string format is wrong. It has to match your string format exactly. You can use dd-MMM-yy hh:mm:ss tt format instead.
Here an example in LINQPad.
string s = "16-Aug-78 12:00:00 AM";
var date = DateTime.ParseExact(s, "dd-MMM-yy hh:mm:ss tt",
CultureInfo.InvariantCulture);
date.Dump();
Custom Date and Time Format Strings
Or, since dd-MMM-yy hh:mm:ss tt is a standart date and time format for InvariantCulture, you can directly DateTime.Parse method like;
string s = "16-Aug-78 12:00:00 AM";
var date = DateTime.Parse(s, CultureInfo.InvariantCulture);
date.Dump();
Here a demonstration.
Is there any way for finding it to converting to any general format?
There is no way to get format of a string except you create your own formatting. Only you can know what is your string format exactly, computer can't.
For example; 01/02/2014 can be 1 February 2014 or 2 January 2014 depends on which custom format you can parse it.
Try as below
var dstring = "16-Aug-78 12:00:00 AM";
DateTime result;
var matchingCulture = CultureInfo.GetCultures(CultureTypes.AllCultures).FirstOrDefault(ci => DateTime.TryParse(dstring, ci, DateTimeStyles.None, out result))
You have wrong format string, you are using ss for day it should be dd. This article Custom Date and Time Format Strings explains what you need for custom format.
Use
"dd-MMM-yy hh:mm:ss tt"
Instead of
"ss-MMM-yy hh:mm:ss"
You can use DateTime.ParseExact to parse the string.
DateTime dt = DateTime.ParseExact("16-Aug-78 12:00:00 AM", "dd-MMM-yy hh:mm:ss tt", CultureInfo.InvariantCulture, DateTimeStyles.None);
You can try with DateTime.TryParseExact():
string strDate = "16-Aug-78 12:00:00 AM";
DateTime datDate;
if(DateTime.TryParseExact(strDate , new string[] {"dd-MMM-yy hh:mm:ss tt" },
System.Globalization.CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.None, out datDate))
{
Console.WriteLine(datDate);
}
else
{
Console.WriteLine("Error in datetime format");
}
How to convert "yyyy-MM-ddTHH:mm:ss" into "dd MMM yyyy" format? For Instance, i want to convert 2013-04-16 05:30:05 into 16 April 2013. What is the correct method to achieve this?
First ParseExact then do ToString (I assume that you have string object, if you have DateTime object, skip first line)
var dateTime = DateTime.ParseExact(yourDateString, "yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture);
var yourNewString = dateTime.ToString("dd MMM yyyy");
Note that representation of DateTime you see in debugger is dependant on your current culture.
First, a DateTime has no format. But if you've already a string that represents a DateTime with the format yyyy-MM-ddTHH:mm:ss and you want to convert it to a string-date with format dd MMM yyyy you need to parse it to DateTime first.
Therefore use DateTime.ParseExact:
DateTime dt = DateTime.ParseExact("2013-04-16 05:30:05", "yyyy-MM-dd HH:mm:ss", null);
Now you can use DateTime.ToString:
string result = dt.ToString("dd MMM yyyy");
Note that you need to pass a different CultureInfo object to ParseExact/ToString if you want to parse with another DateTimeFormat than your current (f.e. force english month names instead of german: dt.ToString("dd MMM yyyy", CultureInfo.InvariantCulture)).
As others mentioned, a DateTime has no format. To parse a string literal to a Date you need to call DateTime.Parse (if the string is in a culture-specific format) or DateTime.ParseExact if you need to pass a format string.
The format can be a custom format like yyyy-MM-dd HH:mm:ss or one of the standard format strings, eg. s for yyyy-MM-ddTHH:mm:ss.
2013-04-16 05:30:05 it not in one of the standard formats, so you have to parse by passing a custom format string:
var dt = DateTime.ParseExact("2013-04-16 05:30:05", "yyyy-MM-dd HH:mm:ss", null);
On the other hand, yyyy-MM-ddTHH:mm:ss is the s standard format so you can just write:
var dt = DateTime.ParseExact("2013-04-16T05:30:05", "s", null);