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  4. datetime.tryparse("datetime in dd/MM/yyyy format",datetimeobject) returns false for dd/mm/yyyy

datetime.tryparse("datetime in dd/MM/yyyy format",datetimeobject) returns false for dd/mm/yyyy

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  • S schampacc

    It returns true for 05/04/2011 but returns false for 25/04/2011

    A Offline
    A Offline
    Alan N
    wrote on last edited by
    #7

    schampacc wrote:

    It returns true for 05/04/2011 but returns false for 25/04/2011

    With that information I can deduce that your system's Culture uses MM/dd/yyyy format and it shouldn't be a surprise that TryParse rejects a month number of 25. When the day number is less than 13 it is not possible to understand a date without prior knowledge of the Culture. Therefore I can guess that "25/04/2011" is 25 April 2011 but I can't say whether "05/04/2011" is 5 April or 4 May unless I know the field order within the string. Alan.

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    • S schampacc

      I have requirement where user can pass all types of datetime formats. Also I need to validate all the datetime formats entered by user.

      DateTime.TryParse() returns false, if the date passed is in dd/MM/yyyy format. I have noticed in all the forums this issue is been noted.

      Can anyone reply why this error is been thrown and whats the solution so as to pass all datetime formats

      J Offline
      J Offline
      jschell
      wrote on last edited by
      #8

      schampacc wrote:

      pass all types of datetime formats

      That isn't possible. Different cultures expect different forms of dates and those forms are not deterministically unique without additional information. So either you must limit the possible forms or you must provide a way for the user (or user app) to tell you what form is expected. There is no other possibility.

      S 1 Reply Last reply
      0
      • J jschell

        schampacc wrote:

        pass all types of datetime formats

        That isn't possible. Different cultures expect different forms of dates and those forms are not deterministically unique without additional information. So either you must limit the possible forms or you must provide a way for the user (or user app) to tell you what form is expected. There is no other possibility.

        S Offline
        S Offline
        schampacc
        wrote on last edited by
        #9

        Hi All, I have found the solution to support all datetime formats. First I need to inform is that datetime objects uses the system culture by default. But we have a solution for this. You can loop in all the cultures available and check if the passed datetime is in valid format or not by using the below code.

        DateTimeStyles styles = DateTimeStyles.None;
        DateTime startDate;
        foreach (CultureInfo cInfo in CultureInfo.GetCultures(CultureTypes.AllCultures))
        {
        DateTime.TryParse("stringDate", cInfo, styles, out startDate)
        }

        D P J 3 Replies Last reply
        0
        • S schampacc

          Hi All, I have found the solution to support all datetime formats. First I need to inform is that datetime objects uses the system culture by default. But we have a solution for this. You can loop in all the cultures available and check if the passed datetime is in valid format or not by using the below code.

          DateTimeStyles styles = DateTimeStyles.None;
          DateTime startDate;
          foreach (CultureInfo cInfo in CultureInfo.GetCultures(CultureTypes.AllCultures))
          {
          DateTime.TryParse("stringDate", cInfo, styles, out startDate)
          }

          D Offline
          D Offline
          Daniel Grondal
          wrote on last edited by
          #10

          Will you still not have problems when the day number is less than 13? 04/05/11 and 05/04/11 will probably be ok with several cultures?

          //daniel

          modified on Tuesday, September 13, 2011 5:06 AM

          S 1 Reply Last reply
          0
          • D Daniel Grondal

            Will you still not have problems when the day number is less than 13? 04/05/11 and 05/04/11 will probably be ok with several cultures?

            //daniel

            modified on Tuesday, September 13, 2011 5:06 AM

            S Offline
            S Offline
            schampacc
            wrote on last edited by
            #11

            Thats right. Then in this case one should go for one particular format only. The issue was to validate the date is in valid dateformat or not. It can be in any valid dateformat. This issue can be solved using the above loop.

            D 1 Reply Last reply
            0
            • S schampacc

              Hi All, I have found the solution to support all datetime formats. First I need to inform is that datetime objects uses the system culture by default. But we have a solution for this. You can loop in all the cultures available and check if the passed datetime is in valid format or not by using the below code.

              DateTimeStyles styles = DateTimeStyles.None;
              DateTime startDate;
              foreach (CultureInfo cInfo in CultureInfo.GetCultures(CultureTypes.AllCultures))
              {
              DateTime.TryParse("stringDate", cInfo, styles, out startDate)
              }

              P Offline
              P Offline
              Pete OHanlon
              wrote on last edited by
              #12

              This is not the way to solve this - in fact, it's an incredibly naive solution. As an example, 9/11/2001 - what happened on that day? It was either a terrible disaster in America or a very quiet day in November. You should use the universal datetime format in your application, which is agnostic of ALL cultures.

              Forgive your enemies - it messes with their heads

              My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

              S 1 Reply Last reply
              0
              • P Pete OHanlon

                This is not the way to solve this - in fact, it's an incredibly naive solution. As an example, 9/11/2001 - what happened on that day? It was either a terrible disaster in America or a very quiet day in November. You should use the universal datetime format in your application, which is agnostic of ALL cultures.

                Forgive your enemies - it messes with their heads

                My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

                S Offline
                S Offline
                schampacc
                wrote on last edited by
                #13

                Do you mean to define the datetime object as DateTime.UTC?

                P 1 Reply Last reply
                0
                • S schampacc

                  Thats right. Then in this case one should go for one particular format only. The issue was to validate the date is in valid dateformat or not. It can be in any valid dateformat. This issue can be solved using the above loop.

                  D Offline
                  D Offline
                  Dave Kreskowiak
                  wrote on last edited by
                  #14

                  schampacc wrote:

                  Then in this case one should go for one particular format only.

                  And your test still doesn't hold up. Take a look at 4/20/2011. Is that a valid date of the form April 20th or an invalid date when someone tried to enter the 4th day of the 20th month?

                  A guide to posting questions on CodeProject[^]
                  Dave Kreskowiak

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                  • S schampacc

                    Do you mean to define the datetime object as DateTime.UTC?

                    P Offline
                    P Offline
                    Pete OHanlon
                    wrote on last edited by
                    #15

                    I mean that the date should conform to ISO 8601.

                    Forgive your enemies - it messes with their heads

                    My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

                    P 1 Reply Last reply
                    0
                    • S schampacc

                      Hi All, I have found the solution to support all datetime formats. First I need to inform is that datetime objects uses the system culture by default. But we have a solution for this. You can loop in all the cultures available and check if the passed datetime is in valid format or not by using the below code.

                      DateTimeStyles styles = DateTimeStyles.None;
                      DateTime startDate;
                      foreach (CultureInfo cInfo in CultureInfo.GetCultures(CultureTypes.AllCultures))
                      {
                      DateTime.TryParse("stringDate", cInfo, styles, out startDate)
                      }

                      J Offline
                      J Offline
                      jschell
                      wrote on last edited by
                      #16

                      schampacc wrote:

                      I have found the solution to support all datetime formats.

                      No you haven't. I said it was impossible - which it is. There is no solution. So whatever you are doing is certainly not a solution. What you are probably doing is testing within a LIMITED cultural scope. Which might be what you need to do but isn't what you asked. And if it isn't what you need to do then your solution will fail.

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                      • P Pete OHanlon

                        I mean that the date should conform to ISO 8601.

                        Forgive your enemies - it messes with their heads

                        My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

                        P Offline
                        P Offline
                        PIEBALDconsult
                        wrote on last edited by
                        #17

                        Pete O'Hanlon wrote:

                        conform to ISO 8601

                        Hear hear! I'm glad I didn't have to say it this time. :thumbsup:

                        D 1 Reply Last reply
                        0
                        • P PIEBALDconsult

                          Pete O'Hanlon wrote:

                          conform to ISO 8601

                          Hear hear! I'm glad I didn't have to say it this time. :thumbsup:

                          D Offline
                          D Offline
                          DaveyM69
                          wrote on last edited by
                          #18

                          :laugh:

                          Dave
                          Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (Pete O'Hanlon)
                          BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

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