I have a datetime variable like this:
DateTime date1 = DateTime.Now; // has 9.4.2014 01:12:35
I want to assign this to another datetime or change its value like this:
2014-04-09 13:12:35
How can I do?
Thanks.
EDIT : I don't want string variable. I want it Datetime format.
try this :
date1.ToString("yyyy-MM-dd HH:mm:ss")
Also look at the table below here http://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110).aspx
edit :
As Jon said (and which I didn't mention) :
you should add InvariantCulture ( if you dont want it to be used with current thread culture ) :
CultureInfo heIL = new CultureInfo("he-IL");
heIL.DateTimeFormat.Calendar = new HebrewCalendar();
CultureInfo dft = Thread.CurrentThread.CurrentCulture;
Thread.CurrentThread.CurrentCulture = heIL;
Check these :
DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")
DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss",CultureInfo.InvariantCulture);
result ( I live in israel) :
תשע"ד-ח'-ט' 13:32:31
2014-04-09 13:32:31
The code you've written just assigns a value to a variable. It doesn't return anything, and it doesn't have any inherent string representation. A DateTime value is just a date/time. It can be displayed in whatever format you want, but that's not part of the value of the variable.
It sounds like you're wanting to convert it to a string in a particular format, which you should do with DateTime.ToString - but only when you really need to. Try to keep the value as a DateTime for as long as possible. Typically you only need to convert to a string in order to display the value to a user, or possibly to use it in something like JSON. (If you find yourself converting it to a string for database usage, you're doing it wrong - make sure your schema has an appropriate data type for the field, use a parameterized query, and set the parameter value to just the DateTime - nor formatting required.)
The format you've specified looks like it's meant to be a machine-readable one rather than a culture-specific one, so I'd suggest:
string text = date1.ToString("yyyy-MM-dd HH:mm:ss",
CultureInfo.InvariantCulture);
By specifying the invariant culture, we've said that the result shouldn't depend on the current culture (which otherwise it would) - this can make a big difference if the current culture uses a different calendar system, for example.
Something like the following, which is one of the constructors of the DateTime object:
d = new DateTime(2014, 5, 6, 5, 4, 30);
Which will set d to 06/05/2014 05:04:30. Its parameters are in descending size order, so Year, Month, Day, Hour, Minute then Seconds.
If you want to adjust the time by an amount, look at the add methods, or TimeSpans.
you can just use something like this to format the date:
date1.ToString("dd/MM/yyyy HH:mm:ss")
By using "HH" instead of "hh" you will get 24hour format on the hour.
Hope that helps.
Try this
DateTime date1 = DateTime.Now;
string datestring=date1.ToString("yyyy-MM-dd HH:mm:ss",CultureInfo.InvariantCulture)
http://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110).aspx
As a guess, the "returned" value of your DateTime object is seen by you, by hoovering over the variable in the IDE while debugging.
This is just another form of calling internally the default ToString() method of your DateTime object by the debugger. The value is the same.
See: system.datetime
DateTime Values and their string representations
Internally, all DateTime values are represented as the number of ticks (the number of 100-nanosecond intervals) that have elapsed since 12:00:00 midnight, January 1, 0001. The actual DateTime value is independent of the way in which that value appears when displayed in a user interface element or when written to a file. The appearance of a DateTime value is the result of a formatting operation. Formatting is the process of converting a value to its string representation.
Because the appearance of date and time values is dependent on such factors as culture, international standards, application requirements, and personal preference, the DateTime structure offers a great deal of flexibility in formatting date and time values through the overloads of its ToString method. The default DateTime.ToString() method returns the string representation of a date and time value using the current culture's short date and long time pattern.
Related
I am filling a DataTable using the results of a SQL SP. One of the columns is a DateTime type. When I try to format the DateTime value, it seems to be ignored.
For example:
foreach (DataRow row in sourceTable.Rows)
{
row["DateOfActivity"] = Convert.ToString(((DateTime)row["DateOfActivity"]).ToString("yyyy-MM-dd"));
Console.WriteLine(row["DateOfActivity"]);
}
Results in:
2/17/2016 12:00:00 AM
How can I make sure the DateTime format is retained?
In a databable, columns have specific types. When you assign back to row["DateOfActivity"], you're assigning to a DateTime value. Writing that back to the console will give you the default .ToString() call.
The solution is to wait to format the output until you actually show it to the user. Get rid of the first line inside the loop completely and have the second line just look like this:
Console.WriteLine(row["DateOfActivity"].ToString("yyyy-MM-dd"));
The type definition of the row["DateOfActivity"] column is not present in your question, however I am going to assume it is defined as a DateTime type. This type definition stores the raw date/time value, without a format.
From MSDN:
Internally, all DateTime values are represented as the number of ticks (the number of 100-nanosecond intervals) that have elapsed since 12:00:00 midnight, January 1, 0001. The actual DateTime value is independent of the way in which that value appears when displayed in a user interface element or when written to a file. The appearance of a DateTime value is the result of a formatting operation. Formatting is the process of converting a value to its string representation.
Because the appearance of date and time values is dependent on such factors as culture, international standards, application requirements, and personal preference, the DateTime structure offers a great deal of flexibility in formatting date and time values through the overloads of its ToString method. The default DateTime.ToString() method returns the string representation of a date and time value using the current culture's short date and long time pattern. The following example uses the default DateTime.ToString() method to display the date and time using the short date and long time pattern for the en-US culture, the current culture on the computer on which the example was run.
You should be formatting the value of a DateTime type when you output it. If you want to store a formatted version of this value in your DataTable you will need to define the column as a string and then store the formatted value.
For more information see this link on the DateTime type.
I have a DataTable coming from a stored procedure which I'm writing to an excel file. There's a column with a DateTime datatype, and looking at the values in there, they're just generic dates with the time stamp.
I've tried using the DateTime.Date property, but that still gives me a time stamp. Further, I've tried to create a new DateTime object using the year,month,day constructor but it still adds a time stamp:
DateTime newDate = DateTime(oldDate.Year, oldDate.Month, oldDate.Day);
I'm trying to keep the column datatype to DateTime but remove the time stamp, so this rules out ToString("") formatting. Is there another way?
A DateTime always contains a date and a time portion. If you use the Date property it returns a new DateTime where the time is 0:00:00 so midnight at the same day. You want a string representation of the datetime without the time.
You can use DateTime.ToString:
string result = oldDate.ToString("d"); // uses current culture's date format
or
string result = oldDate.ToShortDateString(); // same as above
or
string result = oldDate.ToString("MM-dd-yyyy"); // custom format
Edit: "so this rules out ToString("") formatting. Is there another way?"
No, because of the reason mentioned above.
It's important to separate the data from how it is displayed. If you need to display it without time use the code above, you can store the original DateTime variable for future processing, select it again from database or use DateTime.Parse/DateTime.ParseExcact to get a DateTime from the string.
The 'problem' is that there is no Date struct in .NET, you only have a DateTime struct. That will always contain both date and time. You can only format it as date.
Or, you could of course write your own struct containing only the date part, or give up and use string.Format to format it as a date (possibly using the short date string d).
If you mean time part with timestamp, a DateTime instance always have both date and time part. DateTime.Date property just sets the time value set to midnight.
You can get it's string representation if you want only it's Date part. You can get standard date and time format or custom date and time format with DateTime.ToString() method.
Usually, you can use ShortDatePattern to get only string representation of Date part which uses standard "d" format of your CurrentCulture.
DateTime.Now.ToString("d");
There is a proposal for System.Date and System.Time types for .NET Framework in dotnet/corefx on GitHub page by the way.
Proposal: System.Date type
You should use DateTime.Now.ToShortDateString();
Using C#, I am trying to format a date in to the following string format:
YYYYMMDD_HHMM.xlsx
Here is my code:
DateTime.Today.AddDays(0).ToString("yyyymmdd") + "_" + DateTime.Today.AddDays(0).ToString("hhmm")
Here is my output:
20130027_1200.xlsx
Month is not correct, nor is the time.
You're using mm, which is minutes, not months - and you're trying to print the time using DateTime.Today, which always returns midnight at the start of the day.
It's not clear why you're adding 0 days, either. I'd use:
DateTime now = DateTime.Now;
string name = now.ToString("yyyyMMdd'_'HHmm'.xlsx'");
(The ' quoting for the _ isn't strictly necessary, but personally I find it simplest to take the approach of quoting everything that isn't a format specifier.)
Or:
DateTime now = DateTime.Now;
string name = string.Format("{0:yyyyMMdd}_{0:HHmm}.xlsx", now);
Note the use of HH instead of hh to get a 24-hour clock rather than 12-hour, too.
Additionally, consider using UtcNow instead of Now, depending on your requirements. Note that around daylight saving transitions, the clock will go back or forward, so you could end up with duplicate file names.
Also note how in my code I've used DateTime.Now once - with your original code, you were finding the current date twice, which could have given different results on each invocation.
Finally, you might also want to specify CultureInfo.InvariantCulture when you format the date/time - otherwise if the current culture is one which doesn't use a Gregorian calendar by default, you may not get the results you were expecting.
DateTime.Today returns DateTime with all time-related properties set to 0. Use DateTime.Now instead.
Property value
An object that is set to today's date, with the time component set to 00:00:00.
from DateTime.Today Property
Use MM in your format to get month. mm returns minutes. You can check all format specifiers on MSDN: Custom Date and Time Format Strings
I have date string in format dd-MMM-yyyy and want to convert this to datetime, when I use below code
DateTime.ParseExact("20-Oct-2012", "yyyy-MM-dd HH:mm tt", null)
it causing an error
String was not recognized as a valid DateTime.
When I modify above code
DateTime.ParseExact("20-Oct-2012", "dd-MMM-yyyy", null)
then I got date time in format (mm/dd/yyyy) : 10/20/2012 12:00:00 AM
But I need it should be converted in yyyy/mm/dd format. Please help me in this regard.
You should try this
DateTime.ParseExact("20-Oct-2012", "dd-MMM-yyyy", null).ToString("yyyy/mm/dd")
For further reading on formats Check This
You need to distinguish between two separate concerns: that of parsing your original string into an abstract DateTime representation, and that of converting the latter back into another string representation.
In your code, you're only tackling the former, and relying on the implicit ToString() method call (which uses the system's current locale) to convert it back to string. If you want to control the output format, you need to specify it explicitly:
// Convert from string in "dd-MMM-yyyy" format to DateTime.
DateTime dt = DateTime.ParseExact("20-Oct-2012", "dd-MMM-yyyy", null);
// Convert from DateTime to string in "yyyy/MM/dd" format.
string str = dt.ToString("yyyy/MM/dd");
Also note that the mm format specifier represents minutes; months are represented by MM.
Edit: 'Converted date contain value "10/20/2012 12:00:00 AM".' Be careful what you mean by that. The constructed DateTime value contains an abstract representation of the parsed date and time that is independent of any format.
However, in order to display it, you need to convert it back into some string representation. When you view the variable in the debugger (as you're presumably doing), Visual Studio automatically calls the parameterless ToString() method on the DateTime, which renders the date and time under the current culture (which, in your case, assumes the US culture).
To alter this behaviour such that it renders the date and time under a custom format, you need to explicitly call the ToString(string) overload (or one of the other overloads), as I've shown in the example above.
You could try this instead :
Convert.ToDateTime("20-Oct-2012").ToString("yyyy/MM/dd")
Hope this will help !!
I need to perform some date operations in ASP.net using C#.
The date i would enter should be of format 'Jul-05' (mmm-yy Format and type-string)...
how can i check with this????
Or how can i validate this with whatever user is entering as a string???
After validating that, i need to compare tht with a value in Database(say a column name buy_period which has a value (say) 04/31/2007).
How can i write a Query for comparing both?? (as both dates would be of different formats)
Can u pls help me in this ???
DateTime myDateTime = DateTime.ParseExact( input, "MMM-yy" );
You can then happily pass it to a stored procedure (etc.) as a parameter to do your comparison on the server (or just use the DateTime returned as the result of an existing query)
Use the TryParseExact method to validate the string and parse it to a DateTime value:
DateTime month;
if (DateTime.TryParseExact("MMM-yy", CultureInfo.InvariantCulture, DateTimeStyles.None, out month)) {
// parsing was successful
}
The DateTime value will use the first day of month and the time 0:00 to fill up a complete value, so a string like "jul-05" will be parsed into a complete DateTime value like 2005-07-01 00:00:00.0000, so it will be the starting point of that month.
To compare this to a date in the database you also need the starting point of the next month, which you get with:
DateTime nextMonth = month.AddMonths(1);
Now you can just compare a date to the starting and ending point of the month in this manner:
where date >= #Month and date < #NextMonth
The .NET framework has some nice methods on the DateTime struct :: Parse, TryParse, ParseExact, TryParseExact.
This info is discussed on MSDN.
Becuase you're providing a custom date string, we should then use the ParseExact or TryParseExact. The later doesn't throw an exception if it fails to parse.
So.. lets try this...
using System.Globalization;
CultureInfo MyCultureInfo = new CultureInfo("en-US");
string myString = "Jul-05";
DateTime myDateTime = DateTime.ParseExact(myString, "MMM-yy", MyCultureInfo))
Console.WriteLine();
the value myDateTime can then be passed to a database as a DateTime property and checked against that.
EDIT: Damn, beaten by Rowland by a min, as i was typing it!
EDIT 2: Please note the "MMM-yy". As stated on the MSDN page, MMM is "Represents the abbreviated name of the month as defined in the current System.Globalization.DateTimeFormatInfo.AbbreviatedMonthNames property." mmm (lower case) is invalid.
1: read this
2: is the column is a datetime or varchar?
well your validation and comparison have to be two different operations. so you could do alot of things for validation.
Validation Options:
1.) Split your string on "-" and check to see if the mmm part is in your list of months, and then check to see if the number is valid.
2.) Regular Expression, this is advanced but can be reduced to one line. Look up RegEx if you are interested.
After you've validated the string, convert it to a DateTime object and compare it to the other value using DateTime.Compare().
Hope that helps.
You could use
DateTime date = DateTime.ParseExact(value, "MMM-yy", null); //checked at http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx
and then use that date in a sql command parameter.