CODEWITHSUNDEEP
c#datetime
Dee J.
Dee J.

Reputation: 365

How to retain Gregorian date format of date input if region OS is Thai

I have a date string pulled from Excel which I'm trying to parse. Said date is originally in Gregorian format. Is there any way to retain this even after using TryParse/TryParseExact?

Note: Since our end-users are from Thailand, I'm doing this while my machine's region is set to Thai. Hence, my system date as of this post is "12/7/2561".

Suppose I have the following string input in Gregorian M/d/yyyy format:

string validDate = "7/15/2018"

When I initially tried parsing this using DateTime.TryParseExact, it gave me 15/7/2561.

I've tried the following methods listed in these links, particularly the CreateSpecificCulture:

  1. MSDN: Convert Thailand DateTime TO English DateTime
  2. ASP.NET forums: DateTime issue while converting from thai culture to english culture

Here's my code right now:

public DateTime? ConvertThaiToGregorian(string text, string dateFormat)
{
    /// Note: Thailand uses the Thai Buddhist calendar, which is 543 years ahead of 
    ///       the Gregorian calendar. 
    /// dateFormat here is "M/d/yyyy".

    DateTime convertedDate;

    // Create Thai CultureInfo
    IFormatProvider thCulture = CultureInfo.CreateSpecificCulture("th-TH");

    // Parse date = returns "15/7/2018"...
    DateTime.TryParseExact(text, dateFormat, thCulture, DateTimeStyles.None, out convertedDate);

    // Create en-US CultureInfo
    IFormatProvider engCulture = CultureInfo.CreateSpecificCulture("en-US");

    // Parse date back to US format = gives me "01/01/0544"...
    DateTime.TryParseExact(convertedDate.ToString(), dateFormat, engCulture, DateTimeStyles.None, out convertedDate);

    return convertedDate;
}

Any help will be greatly appreciated. Thank you!

Upvotes: 0

Views: 3710

Answers (2)

SilentTremor
SilentTremor

Reputation: 4902

Hope it will help you understand how CultureInfo gets the DateTime from a string, the bare minimum requirement is in what culture date string is, but server or operating system shouldn't matter if string is parsed correct. Operating system will interfere only if culture isn't specified when string is parsed.

C# fiddle here: https://dotnetfiddle.net/wdDlts

using System;
using System.Globalization;

public class Program
{
    public static void Main()
    {
        string thaiBudistDate = "12/7/2561";

        // US format
        CultureInfo provider = CultureInfo.GetCultureInfo("en-US");
        DateTime date = DateTime.Parse(thaiBudistDate, provider);
        Console.WriteLine("Original string: '" + provider + "' in 'en-US' => Day: " + date.Day + " Month: " + date.Month + " Year: " + date.Year );

        // Thai Culture
        provider = CultureInfo.GetCultureInfo("th-TH");
        date = DateTime.Parse(thaiBudistDate, provider);
        Console.WriteLine("Original string: '" + provider + "' in 'th-TH' => Day: " + date.Day + " Month: " + date.Month + " Year: " + date.Year );

        // Thai Culture format! M/d/yyyy
        provider = CultureInfo.GetCultureInfo("th-TH");
        var format = "M/d/yyyy";
        date = DateTime.ParseExact(thaiBudistDate, format, provider);
        Console.WriteLine("Original string: '" + provider + "' in 'th-TH' format specified 'M/d/yyyy' => Day: " + date.Day + " Month: " + date.Month + " Year: " + date.Year );

        // Thai Culture format d/M/yyyy 
        provider = CultureInfo.GetCultureInfo("th-TH");
        format = "d/M/yyyy";
        date = DateTime.ParseExact(thaiBudistDate, format, provider);
        Console.WriteLine("Original string: '" + provider + "' in 'th-TH' format specified 'd/M/yyyy' => Day: " + date.Day + " Month: " + date.Month + " Year: " + date.Year );

        // Using Gregorian time
        string usaDate = "12/7/2018";
        // US Culture
        provider = CultureInfo.GetCultureInfo("en-US");
        date = DateTime.Parse(usaDate, provider);
        Console.WriteLine("Original string: '" + usaDate + "' in 'en-Us' => Day: " + date.Day + " Month: " + date.Month + " Year: " + date.Year );


        // You got the point, dones't matter what provider you use! Hope this will help you undestand how wondows Culture works
        usaDate = "12/7/2018";
        // Thai Culture
        provider = CultureInfo.GetCultureInfo("th-TH");
        date = DateTime.Parse(usaDate, provider);
        Console.WriteLine("Original string: '" + usaDate + "' in 'th-TH' => Day: " + date.Day + " Month: " + date.Month + " Year: " + date.Year );

    }
}

Upvotes: 1

Pipon
Pipon

Reputation: 11

If you already have the datetime converted to Thai culture (where day, month and year properties are correctly set) I think its enough to format it again to Datetime.ToString("M/d/yyyy") in case you want the string representation.

Upvotes: 0

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