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Lance_FrisbeeFlag for United States of America asked on

RegularExpressionValidator (Date)

Hi, I am looking for code that will set a regular expression validator to validate dates in this format: mm/dd/yyyy. I have this code already in: \d{2}/\d{2}/\d{4}

I need to have it accept (m or mm) and (d or dd). So if it was March 1st, it would be acceptable to write 3/1/2004 and not have to type out 03/01/2004. Minor i know, but thats what the boss wants.

Thanks for your responses.

Lance
.NET Programming

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8/22/2022 - Mon
eternal_21

What about \d{1, 2}/\d{1, 2}/\d{4} ?
ASKER
Lance_Frisbee

Nope, that doesn't work.
ASKER
Lance_Frisbee

It's probably something stupidly simple like that though, and i am just overlooking it.
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eternal_21

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ASKER
Lance_Frisbee

Thank you eternal.
eternal_21

For completeness, I would use a method like this:

    bool IsValidDate(string dateString)
    {
      if(System.Text.RegularExpressions.Regex.Match(dateString, @"\d{1,2}/\d{1,2}/\d{4}").Success)
        try
        {
          DateTime.ParseExact(dateString, "dd/mm/yyyy", System.Globalization.CultureInfo.InvariantCulture);
          return true;
        }
        catch
        {
          return false;
        }
      else
        return false;
    }

Glad I could help, Lance.
eternal_21

There is an error in the above method!  Replace with:

### C#.NET ###

    bool IsValidDate(string dateString)
    {
      // Use Regex first to check for obvious non-matches
      // (eg: text, year in the wrong position).
      if(System.Text.RegularExpressions.Regex.Match(dateString, @"^\d{1,2}/\d{1,2}/\d{4}$").Success)
        try
        {
          // Then try to parse it into a DateTime to be sure
          // (makes sure that user cannot enter 99/01/2004).
          string[] allowedFormats;
          allowedFormats = new string[] {
                            "MM/dd/yyyy",
                            "M/dd/yyyy",
                            "MM/d/yyyy",
                            "M/d/yyyy"
                          };
          DateTime.ParseExact(dateString, allowedFormats, System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None);          
          return true;
        }
        catch
        {
          return false;
        }
      else
        return false;
    }

###
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ASKER
Lance_Frisbee

Thank you eternal... i've already edited it :) i ended up with another validator. then parsing it to datetime

the validator ended up being: ([1-9]|1[012]||0[1-9]|1[012])[- /.]([1-9]|[12][0-9]|3[01]||0[1-9]|[12][0-9]|3[01])[- /.](20)\d\d

BusyPhoto