DateTime.TryParse all possible type of dates

Question

I want to check if a date has a correct format. There is many possibilities of correct dates like:

• 02.08.2010
• 2.8.2010
• 02.8.2010 02.08
• 02.August
• ...

I can test each on with code like this:

if (DateTime.TryParse(DateTime.ParseExact(date, "dd.M.", 
                              new CultureInfo("sl-SI")).ToString(), out dt))

But then i can have 40 if statements. Is it possible to check all dates with one if statement or one loop?

Answer 1

Yes ParseExact can take a list of formats to check against.

var formats = new[] { "M.d.yyyy", "dd.MM.yyyy" };
var dateValue = DateTime.ParseExact(
    dateString, formats, new CultureInfo("sl-SI"), DateTimeStyles.None);

Answer 2

You can use something like the following, but be aware that more than one format might be able to parse the same date. For example 10/11/12 can be parsed as yy/MM/dd or MM/dd/yy, which are both valid US date formats. MM/dd/yy is more common, so it appears first in the list and is the one returned by the code below (if you use it with a US culture instead of the culture in the example).

string testValue = "10.11.12";

DateTime result;
CultureInfo ci = CultureInfo.GetCultureInfo("sl-SI");
string[] fmts = ci.DateTimeFormat.GetAllDateTimePatterns();
Console.WriteLine(String.Join("\r\n", fmts));
if (DateTime.TryParseExact(testValue, fmts, ci,
   DateTimeStyles.AssumeLocal, out result))
{
   Console.WriteLine(result.ToLongDateString());
}

Answer 3

Thy boath for answer. Now i am testing this code, but i have one more problem. What if i have just 9.2 not 9.2.2010 then this code will not work:

CultureInfo ci = CultureInfo.GetCultureInfo("sl-SI");
        string[] fmts = ci.DateTimeFormat.GetAllDateTimePatterns();

        if (DateTime.TryParseExact(date, fmts, ci, DateTimeStyles.AssumeLocal, out dt))
        {
            DateTime = Convert.ToDateTime(date);
            Check = true;
        }

Must i manually add this times or what can i do?

Answer 4

thx for answer. I fixed now. Thx all again.