string was not recognized as a valid datetime while assigning the value to Nullable DateTime

Question

I have a textbox from which I am sending date as string in 'MM/dd/yyyy' formate, and when I am assigning that value to nullable datetime property value getting the error as string was not recognized as a valid datetime, I am converting the string as below then also getting the same error

private Tbl_UserDetails GetAnnouncementInformation(Tbl_UserDetails userDetails, Dictionary<string, object> details)
{
  userDetails.JoiningDate = string.IsNullOrEmpty(details["JoiningDate "].ToString()) ?
                            (DateTime?)null : 
                             DateTime.ParseExact(details["JoiningDate "].ToString(),
                             "MM/dd/yyyy", null);

  userDetails.JoiningDate = string.IsNullOrEmpty(details["JoiningDate "].ToString()) ?
                            (DateTime?)null : 
                             DateTime.ParseExact(details["JoiningDate "].ToString(),
                             "MM/dd/yyyy", CultureInfo.InvariantCulture);
}

In both the way I am getting the same error. Please help me in this.

What is the value of `details["JoiningDate "].ToString()` and your `CurrentCulture`? — Soner Gönül, Aug 25 '14 at 07:15
Did you put a breakpoint and see what the contents of `JoiningDate`? What were the contents? — shree.pat18, Aug 25 '14 at 07:16
@Rocky So, you are saying; `DateTime.ParseExact("08/25/2014", "MM/dd/yyyy", CultureInfo.InvariantCulture)` throws `FormatException`? It doesn't. The problem can be somewhere else? — Soner Gönül, Aug 25 '14 at 07:25
FYI you don't need to cast as `null` as `DateTime?`, `null` is an acceptable return type for any nullable type. — James, Aug 25 '14 at 08:00
Just another reminder what a *terrible* idea it is to store dates as string in a dbase column. — Hans Passant, Aug 25 '14 at 08:01
Clearly *something* isn't right with your code, however, the example you have given can't match what your code really looks like because the example code/data [works fine](https://dotnetfiddle.net/IEqdCD). — James, Aug 25 '14 at 08:33

Margus · Accepted Answer · 2014-08-25T09:17:29.373

3

You could do:

DateTime tempDate;
userDetails.JoiningDate = DateTime.TryParseExact(
  details["JoiningDate "].ToString(), 
  "MM/dd/yyyy", 
  CultureInfo.InvariantCulture, 
  DateTimeStyles.None, 
  out tempDate) 
? tempDate 
: (DateTime?)null;

With extention of :

public static class MyExtensions
{
    public static DateTime? GetNullableDateTime(
        this String str, string format = "MM/dd/yyyy")
    {
        DateTime tempDate;
        var result = DateTime.TryParseExact(str, format, 
            CultureInfo.InvariantCulture, DateTimeStyles.None, out tempDate) 
        ? tempDate 
        : default(DateTime?);
        return result;
    }
}

It would look like:

userDetails.JoiningDate = 
    details["JoiningDate "].ToString().GetNullableDateTime();

Example program

Assert.IsNull("sddfsdf".GetNullableDateTime());
Assert.IsNotNull("10/20/2014".GetNullableDateTime());
Assert.IsNotNull("20.10.2014".GetNullableDateTime("dd.MM.yyyy"));

edited Aug 25 '14 at 09:17

answered Aug 25 '14 at 08:07

Margus

19,694
14
55
103

I have used this, but in an extension method. – Margus Aug 25 '14 at 08:12
Why do you cast `null` as `(DateTime?)`? Just return `null`. – James Aug 25 '14 at 08:29
@James If you have static content checkers they will give an error there. Reason is that **null** does not convey any type information. I am not sure however if **default(DateTime?)** would have intended value. – Margus Aug 25 '14 at 08:35
I was going to also suggest `default(DateTime?)` but that ultimately would just return `null`. However, regardless if I used static type checkers I'd say scenarios like these are exceptions to the rule. – James Aug 25 '14 at 08:47
I am getting null as return value, not getting the date – Rocky Aug 25 '14 at 08:54
What value will **details["JoiningDate "].ToString()** result as? – Margus Aug 25 '14 at 09:02
I have "08/22/2014 00:00:00" value in that, which is string type – Rocky Aug 25 '14 at 09:31
Well try **.GetNullableDateTime("dd.MM.yyyy HH:mm:ss")** or change default value **string format = "MM/dd/yyyy HH:mm:ss"**. – Margus Aug 25 '14 at 09:34

string was not recognized as a valid datetime while assigning the value to Nullable DateTime

1 Answers1

Linked