Hello from Feb 31-th

public class DateHelper
{
    public static string GetCurrentDatePattern()
    {
        switch (CultureInfo.CurrentCulture.TwoLetterISOLanguageName)
        {
            case "ru":
                return @"^\\s*(3[01]|[12][0-9]|0?[1-9])\\.(1[012]|0?[1-9])\\.((?:19|20)\\d{2})\\s*$";
            case "en":
            default:
                return @"^\\s*(1[012]|0?[1-9])\\/(3[01]|[12][0-9]|0?[1-9])\\/((?:19|20)\\d{2})\\s*$";
        }
    }
}