DateTime.ToString() format that can be used in a filename or extension?

Question

I want to add a timestamp to filenames as files are created but most of the DateTime methods I\'ve tried output something with spaces and slashes. For instance:

Answer 1

Using interpolation string & format specifier:

var filename = $"{DateTime.Now:yyyy.dd.M HH-mm-ss}"

Example Output for January 1st, 2020 at 10:40:45AM:

2020.28.01 10-40-45

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Or if you want a standard date format:

var filename = $"{DateTime.Now:yyyy.M.dd HH-mm-ss}"

2020.01.28 10-40-45

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Note: this feature is available in C# 6 and later versions of the language.

Answer 2

The below list of time format specifiers most commonly used.,

dd -- day of the month, from 01 through 31.

MM -- month, from 01 through 12.

yyyy -- year as a four-digit number.

hh -- hour, using a 12-hour clock from 01 to 12.

mm -- minute, from 00 through 59.

ss -- second, from 00 through 59.

HH -- hour, using a 24-hour clock from 00 to 23.

tt -- AM/PM designator.

Using the above you will be able to form a unique name to your file name.

Here i have provided example

string fileName = "fileName_" + DateTime.Now.ToString("MM-dd-yyyy_hh-mm-ss-tt") + ".pdf";

OR

If you don't prefer to use symbols you can try this also.,

string fileName = "fileName_" + DateTime.Now.ToString("MMddyyyyhhmmsstt") + ".pdf";

Hope this helps to someone now or in future. :)

Answer 3

You can use this:

DateTime.Now.ToString("yyyy-dd-M--HH-mm-ss");

Answer 4

You can make a path for your file as bellow:

string path = "fileName-"+DateTime.Now.ToString("yyyy-dd-M--HH-mm-ss") + ".txt";

Answer 5

You can try with

var result = DateTime.Now.ToString("yyyy-MM-d--HH-mm-ss");

Answer 6

I have a similar situation but I want a consistent way to be able to use DateTime.Parse from the filename as well, so I went with

DateTime.Now.ToString("s").Replace(":", ".") // <-- 2016-10-25T16.50.35

When I want to parse, I can simply reverse the Replace call. This way I don't have to type in any yymmdd stuff or guess what formats DateTime.Parse allows.