What does CultureInfo InvariantCulture mean

Question

I have a string of text like so   var foo    FooBar     I want to declare a second string called bar and make this equal to first and fourth character of my first foo  so I do this like so   var bar   foo 0  ToString     foo 3  ToString      This works as expected  but ReSharper is advising me to put Culture InvariantCulture inside my brackets  so this line ends up like so   var bar   foo 0  ToString CultureInfo InvariantCulture            foo 3  ToString CultureInfo InvariantCulture     What does this mean  and will it affect how my program runs

User · Answer

When numbers  dates and times are formatted into strings or parsed from strings a culture is used to determine how it is done  E g  in the dominant en-US culture you have these string representations    1 000 000 00 - one million with a two digit fraction 1 29 2013 - date of this posting   In my culture  da-DK  the values have this string representation    1 000 000 00 - one million with a two digit fraction 29-01-2013 - date of this posting   In the Windows operating system the user may even customize how numbers and date times are formatted and may also choose another culture than the culture of his operating system  The formatting used is the choice of the user which is how it should be   So when you format a value to be displayed to the user using for instance ToString or String Format or parsed from a string using DateTime Parse or Decimal Parse the default is to use the CultureInfo CurrentCulture  This allows the user to control the formatting   However  a lot of string formatting and parsing is actually not strings exchanged between the application and the user but between the application and some data format  e g  an XML or CSV file   In that case you don t want to use CultureInfo CurrentCulture because if formatting and parsing is done with different cultures it can break  In that case you want to use CultureInfo InvariantCulture  which is based on the en-US culture   This ensures that the values can roundtrip without problems   The reason that ReSharper gives you the warning is that some application writers are unaware of this distinction which may lead to unintended results but they never discover this because  their CultureInfo CurrentCulture is en-US which has the same behavior as CultureInfo InvariantCulture  However  as soon as the application is used in another culture where there is a chance of using one culture for formatting and another for parsing the application may break   So to sum it up    Use CultureInfo CurrentCulture  the default  if you are formatting or parsing a user string  Use CultureInfo InvariantCulture if you are formatting or parsing a string that should be parseable by a piece of software  Rarely use a specific national culture because the user is unable to control how formatting and parsing is done

User · Answer

According to Microsoft   The CultureInfo InvariantCulture property is neither a neutral nor a specific culture  It is the third type of culture that is culture-insensitive  It is associated with the English language but not with a country or region    from http   msdn microsoft com en-us library 4c5zdc6a vs 71  aspx  So InvariantCulture is similair to culture  quot en-US quot  but not exactly the same  If you write  var d   DateTime Now  var s1   d ToString CultureInfo InvariantCulture         quot 05 21 2014 22 09 28 quot  var s2   d ToString new CultureInfo  quot en-US quot               quot 5 21 2014 10 09 28 PM quot   then s1 and s2 will have a similar format but InvariantCulture adds leading zeroes and  quot en-US quot  uses AM or PM  So InvariantCulture is better for internal usage when you e g save a date to a text-file or parses data  And a specified CultureInfo is better when you present data  date  currency     to the end-user

User · Answer

JetBrains offer a reasonable explanation        Ad-hoc conversion of data structures to text is largely dependent on   the current culture  and may lead to unintended results when the code   is executed on a machine whose locale differs from that of the   original developer  To prevent ambiguities  ReSharper warns you of any   instances in code where such a problem may occur     but if I am working on a site I know will be in English only  I just ignore the suggestion

User · Answer

For things like numbers  decimal points  commas in amounts   they are usually preferred in the specific culture    A appropriate way to do this would be set it at the culture level  for German  like this   Thread CurrentThread CurrentCulture NumberFormat   new CultureInfo  de   NumberFormat

User · Answer

Not all cultures use the same format for dates and decimal   currency values   This will matter for you when you are converting input values  read  that are stored as strings to  DateTime  float  double or decimal   It will also matter if you try to format the aforementioned data types to strings  write  for display or storage   If you know what specific culture that your dates and decimal   currency values will be in ahead of time  you can use that specific CultureInfo property  i e  CultureInfo  en-GB     For example if you expect a user input   The CultureInfo InvariantCulture property is used if you are formatting or parsing a string that should be parseable by a piece of software independent of the user s local settings   The default value is CultureInfo InstalledUICulture so the default CultureInfo is depending on the executing OS s settings  This is why you should always make sure the culture info fits your intention  see Martin s answer for a good guideline     CultureInfo InvariantCulture Example CultureInfo InvariantCulture on StackOverflow CultureInfo InvariantCulture MSDN Article Predefined CultureInfo Names

[.net] What does CultureInfo.InvariantCulture mean?

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