How can I convert nullable datetime to decimal in c#

Question

I am trying to convert a DateTime? value to Decimal. (Note: that DateTime? is Nullable)

From this format 4/1/2011 12:00:00 AM to this format (of Decimal type) 20110401.

How can this be achieved?

are you sure you want a `decimal` and not a `string`? A string representation in your format can be created via `ToString`: `DateTime.UtcNow.ToString("yyyyMMdd")` — Nico, Oct 31 '16 at 13:52
Then just after doing the `ToSting("yyyyMMdd")` convert to decimal — Gilad Green, Oct 31 '16 at 13:54
`dateTime.Year * 10000 + dateTime.Month * 100 + dateTime.Day`. — juharr, Oct 31 '16 at 13:54
Sure it does. Practically everything (are there any exceptions?) supports ToString(). This compiles and runs fine: DateTime dtNow = DateTime.Now; string zNow = dtNow.ToString(); — Michael Gorsich, Oct 31 '16 at 14:07
_Why_ does it need to be a decimal? Sounds like an X-Y problem. — xxbbcc, Oct 31 '16 at 14:07

ScottishTapWater · Answer 1 · 2016-10-31T14:23:51.650

1

Like this:

DateTime? myDateTime = GetDateTime();
Decimal.Parse(myDateTime.Value.ToString("yyyyMMdd"));

or:

DateTime myDateTime = GetDateTime();
Decimal.Parse(myDateTime.ToString("yyyyMMdd"));

Depending on if DateTime is Nullable or not.

But you really should consider storing it in some other fashion than Decimal it would be like storing a phone number as a Long, which you really shouldn't do. Mainly because mathematical operations don't make sense when performed on an object stored this way.

edited Oct 31 '16 at 14:23

answered Oct 31 '16 at 13:57

ScottishTapWater

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mydatetime is not string so it gives error when I use ToString("yyyyMMdd") – Nakres Oct 31 '16 at 14:01
@Nakres - What error does it tell you? A DateTime does not need to be a string to call `ToString(...)`. – Broots Waymb Oct 31 '16 at 14:02
@Nakres what Type is your actual date time stored as originally? The actual `DateTime` type contains the `.ToString` method (basically, show us your code). – ScottishTapWater Oct 31 '16 at 14:06
The data is coming from USSI. after servicess in my code i can see it like that 4/1/2015 12:00:00 AM – Nakres Oct 31 '16 at 14:11
Yes, @Nakres but what `Type` is it: `String`, `Char[]`, `DateTime`..? – ScottishTapWater Oct 31 '16 at 14:13

score 1 · Answer 2 · answered Oct 31 '16 at 14:04

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You may try this,,

DateTime? dateTime = DateTime.Today;
string dateStr = dateTime.ToString("MMddyyyy");
decimal dec = Convert.ToDecimal(dateStr);

answered Oct 31 '16 at 14:04

Akram Qalalwa

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I am gonna loose my mind. how can i use tostring for datetime. does code really work in your machine? – Nakres Oct 31 '16 at 14:08
ToString method locates inside the base class of all classes, so it exists in any class you create! – Akram Qalalwa Oct 31 '16 at 14:10
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Except, that is a nullable DateTime so do `dateTime.Value.ToString("MMddyyyy")` – Crowcoder Oct 31 '16 at 14:11
@Crowcoder Sometimes he calls it DateTime and sometimes DateTime?. Good catch! – Michael Gorsich Oct 31 '16 at 14:16
@Crowcoder, why do you need `dateTime.Value.ToString()`? `DateTime.ToString()` works fine for me? – ScottishTapWater Oct 31 '16 at 14:17
type was datetime? and dateTime.Value.ToString("MMddyyyy") worked:) – Nakres Oct 31 '16 at 14:18
@JamesHughes, the nullable DateTime won't accept a format string. – Crowcoder Oct 31 '16 at 14:18
@Crowcoder, ahh, didn't see the `?` in this code, nothing to suggest the OP is using nullable though, but it might explain why he doesn't seem to be able to get the obvious option to work – ScottishTapWater Oct 31 '16 at 14:19
@JamesHughes, yeah, my comment was more about why this specific answer wasn't working for OP. – Crowcoder Oct 31 '16 at 14:21

Jules · Answer 3 · 2016-10-31T14:33:20.910

0

You can do this with a little math:

DateTime? dt = DateTime.Today;
decimal d = dt.Value.Year*10000 + dt.Value.Month*100 + dt.Value.Day

...or convert it:

DateTime? dt = DateTime.Today;
decimal d = Convert.ToDecimal(dt.Value.ToString("yyyyMMdd"));

In case, you try to use this decimal value for sorting purposes, please consider that it is possible to order strings and DateTimes, too.

edited Oct 31 '16 at 14:33

answered Oct 31 '16 at 13:57

Jules

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it does not accept year month and day and also tostring. – Nakres Oct 31 '16 at 14:06
@Nakres Which type does your DateTime has? – Jules Oct 31 '16 at 14:08
@Nakres are you really talking about this [DateTime](https://msdn.microsoft.com/de-de/library/system.datetime(v=vs.110).aspx) – Jules Oct 31 '16 at 14:18
value was missing Convert.ToDecimal(dt.value.ToString("yyyyMMdd")); worked – Nakres Oct 31 '16 at 14:20
@Nakres ok I updated my code. Please mark your favorite answer as somution so this topic can be closed – Jules Oct 31 '16 at 14:36

score 0 · Answer 4 · answered Oct 31 '16 at 14:16

You can use ToBinary() to get a binary representation of the DateTime - this can, then, be assigned to a decimal.

DateTime dt = DateTime.Now;
decimal dec = dt.ToBinary ();

This is the most straightforward conversion that doesn't involve converting to a string and back. If you're using a nullable date/time, just use the Value property to get the actual value out of it (with error checking, etc.)

How can I convert nullable datetime to decimal in c#

4 Answers4