Why can t DateTime ParseExact parse 9 1 2009 using M d yyyy

Question

I have a string that looks like this   9 1 2009   I want to convert it to a DateTime object  using C     This works   DateTime Parse  9 1 2009   new CultureInfo  en-US       But I don t understand why this doesn t work   DateTime ParseExact  9 1 2009    M d yyyy   null     There s no word in the date  like  September    and I know the specific format  so I d rather use ParseExact  and I don t see why CultureInfo would be needed   But I keep getting the dreaded  String was not recognized as a valid DateTime  exception   Thanks  A little follow up  Here are 3 approaches that work   DateTime ParseExact  9 1 2009    M   d   yyyy   null   DateTime ParseExact  9 1 2009    M d yyyy   CultureInfo InvariantCulture   DateTime Parse  9 1 2009   new CultureInfo  en-US       And here are 3 that don t work   DateTime ParseExact  9 1 2009    M d yyyy   CultureInfo CurrentCulture   DateTime ParseExact  9 1 2009    M d yyyy   new CultureInfo  en-US     DateTime ParseExact  9 1 2009    M d yyyy   null     So  Parse   works with  en-US   but not ParseExact    Unexpected

User · Accepted Answer

I suspect the problem is the slashes in the format string versus the ones in the data. That's a culture-sensitive date separator character in the format string, and the final argument being null means "use the current culture". If you either escape the slashes ("M'/'d'/'yyyy") or you specify CultureInfo.InvariantCulture, it will be okay.

If anyone's interested in reproducing this:

// Works
DateTime dt = DateTime.ParseExact("9/1/2009", "M'/'d'/'yyyy", 
                                  new CultureInfo("de-DE"));

// Works
DateTime dt = DateTime.ParseExact("9/1/2009", "M/d/yyyy", 
                                  new CultureInfo("en-US"));

// Works
DateTime dt = DateTime.ParseExact("9/1/2009", "M/d/yyyy", 
                                  CultureInfo.InvariantCulture);

// Fails
DateTime dt = DateTime.ParseExact("9/1/2009", "M/d/yyyy", 
                                  new CultureInfo("de-DE"));

User · Answer

Try   Date ParseExact  9 1 2009    M d yyyy   new CultureInfo  en-US

User · Answer

Try    Configure in web config file    lt system web gt         lt globalization   culture  ja-JP      uiCulture  zh-HK        gt    lt  system web gt    eg   DateTime dt   DateTime ParseExact  08 21 2013    MM dd yyyy   null    ref url   http   support microsoft com kb 306162

User · Answer

try this  provider   new CultureInfo  en-US    DateTime ParseExact  9 1 2009    M d yyyy   provider     Bye

User · Answer

Set DateTimePicker s Format property to custom and CustomFormat prperty to M dd yyyy

User · Answer

I tried it on XP  and it doesn t work if the PC is set to International time yyyy-M-d   Place a breakpoint on the line and before it is processed change the date string to use  -  in place of the     and you ll find it works   It makes no difference whether you have the CultureInfo or not  Seems strange to be able specify an expercted format only to have the separator ignored

User · Answer

I bet your machine s culture is not  en-US    From the documentation      If provider is a null reference  Nothing in Visual Basic   the current culture is used    If your current culture is not  en-US   this would explain why it works for me but doesn t work for you and works when you explicitly specify the culture to be  en-US

[.net] Why can't DateTime.ParseExact() parse "9/1/2009" using "M/d/yyyy"

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