Develop Reference

How to parse datetime returns from ToString

When I use the following datetime format in the Windows calendar settings.
Short date: M/d
Long time: H:mm:ss
The following code can't work.
var s = DateTime.Now.ToString(); // 4/28 8:00:00
var b = DateTime.TryParse(s, out dt); // false
The string is returned from a library, so I cannot change it, is it possible to write a parsing method that works for any kind of datetime format in the Windows calendar settings?
Update, from #MathiasR.Jessen's suggestion, I have found a solution, but it is not elegant because I have to concatenate the format string manually.
var dtf = CultureInfo.CurrentCulture.DateTimeFormat;
var fmt = dtf.ShortDatePattern + " " + dtf.LongTimePattern;
var b = DateTime.TryParseExact(s, fmt, null, DateTimeStyles.None, out dt);
Now the question changes to is there a better way?

Note that DateTime.TryParse() or DateTime.Parse() will not understand just any custom format. For custom datetime formats you need to use DateTime.TryParseExact() and DateTime.ParseExact():
Here is a demo Demo with that would be able to parse your input string.

You can Use "DatetTime.Now.ToString("yyyy-MM-dd")" it returns the value in year-shortMonth-date.
You can change the format according to your code.

C#: DateTime problems

In a variable of DateTime typeI have this value = {30/07/2014 0:00:00}
I want only the date:
var aux = pedido.ord_cus_deliv_date.ToString().Split(' ')[0];
with it I obtain 30/04/2014 correctly
but when I want to convert in MM/dd/yyyy using:
var aux2 = DateTime.ParseExact(aux, "MM/dd/yyyy", null);
I have this error:
the string is represents one DateTime not admited in the GregorianCalendar
Why I have this error in aux2?

The problem is your locale setting. Calling ToString() without parameters on a date value produces a string with the pattern day,month,year arranged differently between locales. (And I suppose that you get a string arranged with Day,Separator, Month, Separator, Year).
Passing that string to DateTime.ParseExact with a specific pattern (MM/dd/yyyy) requires the string to be in the exact pattern required Month, Day, Year for your example.
You could force the invariant culture in your conversion with
var aux = pedido.ord_cus_deliv_date.ToString(CultureInfo.InvariantCulture).Split(' ')[0];
this produces a string with the pattern required by the subsequent ParseExact mask
However it is not clear why you need these conversions. A date is not a string and you simply keep it as a date and use the conversion only when you need to represent it somewhere (display, print etc...)
Console.WriteLine("Date is:" + pedido.ord_cus_deliv_date.ToString("MM/dd/yyyy"));

When you call below :
var aux = pedido.ord_cus_deliv_date.ToString().Split(' ')[0];
This gives you code "07-30-2014" and not "07/30/2014" and that's generate the error while conversion. So to get "07/30/2014", you have to write
var aux = pedido.ord_cus_deliv_date.ToString(CultureInfo.InvariantCulture).Split(' ')[0];
Below is overall code for you:
DateTime value = DateTime.Parse("30/07/2014 0:00:00"); //your date time value
var aux = value.ToString(CultureInfo.InvariantCulture).Split(' ')[0];
DateTime dt = DateTime.ParseExact(aux, "MM/dd/yyyy", CultureInfo.InvariantCulture);
var aux2 = dt.ToString(CultureInfo.InvariantCulture).Split(' ')[0]);
I hope this will help you
Regards,
Sandeep

string represents date, and reformat it

The following case:
There is a string that has this format "2012-02-25 07:53:04"
But in the end, i rather want to end up with this format "25-02-2012 07:53:04"
I think i have 2 options. 1 would be to reformat the string and move it all around, but i dont think this is a clean way of doing this.
A other way that i was thinking about is to save the source string to a date parameter, and then write the date parameter back to a string in a certain date format.
But is this even possible to do ?

Do this:
DateTime.Parse("2012-02-25 07:53:04").ToString("dd-MM-yyyy hh:mm:ss");
Keep in mind this isn't culture-aware. And if you do need to store the intermediate result you could do that just as easily:
var myDate = DateTime.Parse("2012-02-25 07:53:04");
var myDateFormatted = myDate.ToString("dd-MM-yyyy hh:mm:ss");
Lastly, check out TryParse() if you can't guarantee the input format will always be valid.

Others have suggested using Parse - but I'd recommend using TryParseExact or ParseExact, also specifying the invariant culture unless you really want to use the current culture. For example:
string input = "2012-02-25 07:53:04";
DateTime dateTime;
if (!DateTime.TryParseExact(input, "yyyy-MM-dd HH:mm:ss",
CultureInfo.InvariantCulture,
DateTimeStyles.None,
out dateTime))
{
Console.WriteLine("Couldn't parse value");
}
else
{
string formatted = dateTime.ToString("dd-MM-yyyy HH:mm:ss",
CultureInfo.InvariantCulture);
Console.WriteLine("Formatted to: {0}", formatted);
}
Alternatively using Noda Time:
string input = "2012-02-25 07:53:04";
// These can be private static readonly fields. They're thread-safe
var inputPattern = LocalDateTimePattern.CreateWithInvariantInfo("yyyy-MM-dd HH:mm:ss");
var outputPattern = LocalDateTimePattern.CreateWithInvariantInfo("dd-MM-yy HH:mm:ss");
var parsed = inputPattern.Parse(input);
if (!parsed.Success)
{
Console.WriteLine("Couldn't parse value");
}
else
{
string formatted = outputPattern.Format(parsed.Value);
Console.WriteLine("Formatted to: {0}", formatted);
}

Parse as DateTime then reformat it. Be careful: use always an IFormatProvider!

Yes, it is quite possible. All you need to do is use DateTime.Parse to parse the string into a DateTime struct and then use ToString() to write the date back out to another string with the format you want.

You can parse this as a date object and then provide the formatting you want when using the date.ToString method:
date.ToString("dd-MM-yyyy hh:mm:ss");

Yes, you can use custom DateTime format strings to parse and reformat DateTime objects.
DateTime date = DateTime.ParseExact("2012-02-25 07:53:04", "yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture);
string formattedDated = date.ToString("dd-MM-yyyy HH:mm:ss");

Formatting string to string Date Format .net 2.0

Given a string value eg "03252013" I need to convert this string to be in this format "DDMMYYYY".
Which function do you use? The result should be "25032013"
string myTestDate="03252013";
string resultDate=??
Thanks

Use DateTime.ParseExact method. Then use ToString to convert to appropriate format.
var dt = DateTime.ParseExact("03252013", "MMddyyyy", CultureInfo.InvariantCulture);
var result = dt.ToString("ddMMyyyy"); //25032013

string resultDate = DateTime.ParseExact(myTestDate, "MMddyyyy", CultureInfo.InvariantCulture).ToString("ddMMyyyy");

Simply parse then re-format:
string input = "03252013"
DateTime date = DateTime.ParseExact(input, "MMddyyyy", CultureInfo.InvariantCulture);
string resultDate = date.ToString("ddMMyyyy");

If your needs really are that simple I would consider just switching the values around...
string input = "03252013";
string output = input.Substring(2, 2) + input.Substring(0, 2) + input.Substring(4, 4);
...dont forget to validate the input before using substring (checking the length is 8 will probably be enough)
NOTE: If it is likely that your input or output formats will change then it would be more ideal to do the DateTime.Parse technique as suggested by many others. But if this is really the only situations then this method should provide better performance... slightly ;)

You, can use the Help of following code part to convert.
string resultDate = DateTime.ParseExact(myTestDate, "MMDDYYYY", System.Globalization.CultureInfo.CurrentCulture, System.Globalization.DateTimeStyles.None).ToString("DDMMYYYY");

Use this:
resultDate = DateTime.Parse(myTestDate,"d").toString();
"d" is a format provider that says to farmat the date like this: DD/MM/YYYY

String was not recognized as a valid DateTime " format dd/MM/yyyy"

I am trying to convert my string formatted value to date type with format dd/MM/yyyy.
this.Text="22/11/2009";
DateTime date = DateTime.Parse(this.Text);
What is the problem ?
It has a second override which asks for IFormatProvider. What is this? Do I need to pass this also? If Yes how to use it for this case?
Edit
What are the differences between Parse and ParseExact?
Edit 2
Both answers of Slaks and Sam are working for me, currently user is giving the input but this will be assured by me that they are valid by using maskTextbox.
Which answer is better considering all aspects like type saftey, performance or something you feel like

Use DateTime.ParseExact.
this.Text="22/11/2009";
DateTime date = DateTime.ParseExact(this.Text, "dd/MM/yyyy", null);

You need to call ParseExact, which parses a date that exactly matches a format that you supply.
For example:
DateTime date = DateTime.ParseExact(this.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture);
The IFormatProvider parameter specifies the culture to use to parse the date.
Unless your string comes from the user, you should pass CultureInfo.InvariantCulture.
If the string does come from the user, you should pass CultureInfo.CurrentCulture, which will use the settings that the user specified in Regional Options in Control Panel.

Parsing a string representation of a DateTime is a tricky thing because different cultures have different date formats. .Net is aware of these date formats and pulls them from your current culture (System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat) when you call DateTime.Parse(this.Text);
For example, the string "22/11/2009" does not match the ShortDatePattern for the United States (en-US) but it does match for France (fr-FR).
Now, you can either call DateTime.ParseExact and pass in the exact format string that you're expecting, or you can pass in an appropriate culture to DateTime.Parse to parse the date.
For example, this will parse your date correctly:
DateTime.Parse( "22/11/2009", CultureInfo.CreateSpecificCulture("fr-FR") );
Of course, you shouldn't just randomly pick France, but something appropriate to your needs.
What you need to figure out is what System.Threading.Thread.CurrentThread.CurrentCulture is set to, and if/why it differs from what you expect.

Although the above solutions are effective, you can also modify the webconfig file with the following...
<configuration>
<system.web>
<globalization culture="en-GB"/>
</system.web>
</configuration>
Ref : Datetime format different on local machine compared to production machine

You might need to specify the culture for that specific date format as in:
Thread.CurrentThread.CurrentCulture = new CultureInfo("en-GB"); //dd/MM/yyyy
this.Text="22/11/2009";
DateTime date = DateTime.Parse(this.Text);
For more details go here:
http://msdn.microsoft.com/en-us/library/5hh873ya.aspx

Based on this reference, the next approach worked for me:
// e.g. format = "dd/MM/yyyy", dateString = "10/07/2017"
var formatInfo = new DateTimeFormatInfo()
{
ShortDatePattern = format
};
date = Convert.ToDateTime(dateString, formatInfo);

After spending lot of time I have solved the problem
string strDate = PreocessDate(data);
string[] dateString = strDate.Split('/');
DateTime enter_date = Convert.ToDateTime(dateString[1]+"/"+dateString[0]+"/"+dateString[2]);

private DateTime ConvertToDateTime(string strDateTime)
{
DateTime dtFinaldate; string sDateTime;
try { dtFinaldate = Convert.ToDateTime(strDateTime); }
catch (Exception e)
{
string[] sDate = strDateTime.Split('/');
sDateTime = sDate[1] + '/' + sDate[0] + '/' + sDate[2];
dtFinaldate = Convert.ToDateTime(sDateTime);
}
return dtFinaldate;
}

use this to convert string to datetime:
Datetime DT = DateTime.ParseExact(STRDATE,"dd/MM/yyyy",System.Globalization.CultureInfo.CurrentUICulture.DateTimeFormat)

Just like someone above said you can send it as a string parameter but it must have this format: '20130121' for example and you can convert it to that format taking it directly from the control. So you'll get it for example from a textbox like:
date = datetextbox.text; // date is going to be something like: "2013-01-21 12:00:00am"
to convert it to: '20130121' you use:
date = date.Substring(6, 4) + date.Substring(3, 2) + date.Substring(0, 2);
so that SQL can convert it and put it into your database.

Worked for me below code:
DateTime date = DateTime.Parse(this.Text, CultureInfo.CreateSpecificCulture("fr-FR"));
Namespace
using System.Globalization;

You can use also
this.Text = "22112009";
DateTime newDateTime = new DateTime(Convert.ToInt32(this.Text.Substring(4, 4)), // Year
Convert.ToInt32(this.Text.Substring(2,2)), // Month
Convert.ToInt32(this.Text.Substring(0,2)));// Day

Also I noticed sometimes if your string has empty space in front or end or any other junk char attached in DateTime value then also we get this error message