/// <summary>
/// Returns a localized text string to express time units in plural.
/// </summary>
/// <param name="units">
/// Number of time units, e.g. 5 for five months.
/// </param>
/// <param name="resources">
/// Resources related to the specified time unit.
/// </param>
/// <returns>Localized text string.</returns>
private static string GetPluralTimeUnits(int units, string[] resources)
{
int modTen = units % 10;
int modHundred = units % 100;
if (units <= 1)
{
throw new ArgumentException(TimeResources.GetString("InvalidNumberOfTimeUnits"));
}
else if (units >= 2 && units <= 4)
{
return(string.Format(PreferredCulture, resources[0], units.ToString(PreferredCulture)));
}
else if (modTen == 1 && modHundred != 11)
{
return(string.Format(PreferredCulture, resources[1], units.ToString(PreferredCulture)));
}
else if ((modTen >= 2 && modTen <= 4) && !(modHundred >= 12 && modHundred <= 14))
{
return(string.Format(PreferredCulture, resources[2], units.ToString(PreferredCulture)));
}
else
{
return(string.Format(PreferredCulture, resources[3], units.ToString(PreferredCulture)));
}
}
/// <summary>
/// Resources use the culture in the system locale by default.
/// The converter must use the culture specified the ConverterCulture.
/// The ConverterCulture defaults to en-US when not specified.
/// Thus, change the resources culture only if ConverterCulture is set.
/// </summary>
/// <param name="culture">The culture to use in the converter.</param>
private void SetLocalizationCulture(CultureInfo culture)
{
//if (!culture.Name.Equals(DefaultCulture, StringComparison.Ordinal))
//{
// ControlResources.Culture = culture;
//}
PluralHourStrings = new string[4] {
TimeResources.GetString("XHoursAgo_2To4"),
TimeResources.GetString("XHoursAgo_EndsIn1Not11"),
TimeResources.GetString("XHoursAgo_EndsIn2To4Not12To14"),
TimeResources.GetString("XHoursAgo_Other")
};
PluralMinuteStrings = new string[4] {
TimeResources.GetString("XMinutesAgo_2To4"),
TimeResources.GetString("XMinutesAgo_EndsIn1Not11"),
TimeResources.GetString("XMinutesAgo_EndsIn2To4Not12To14"),
TimeResources.GetString("XMinutesAgo_Other")
};
PluralSecondStrings = new string[4] {
TimeResources.GetString("XSecondsAgo_2To4"),
TimeResources.GetString("XSecondsAgo_EndsIn1Not11"),
TimeResources.GetString("XSecondsAgo_EndsIn2To4Not12To14"),
TimeResources.GetString("XSecondsAgo_Other")
};
}
/// <summary>
/// Returns a localized text string to express "on {0}"
/// where {0} is a day of the week, e.g. Sunday.
/// </summary>
/// <param name="dow">Day of week.</param>
/// <returns>Localized text string.</returns>
private static string GetOnDayOfWeek(DayOfWeek dow)
{
if (dow == DayOfWeek.Tuesday)
{
return(string.Format(PreferredCulture, TimeResources.GetString("OnDayOfWeek_Tuesday"), GetDayOfWeek(dow)));
}
else
{
return(string.Format(PreferredCulture, TimeResources.GetString("OnDayOfWeek_Other"), GetDayOfWeek(dow)));
}
}
/// <summary>
/// Returns a localized text string to express months in plural.
/// </summary>
/// <param name="month">Number of months.</param>
/// <returns>Localized text string.</returns>
private static string GetPluralMonth(int month)
{
if (month >= 2 && month <= 4)
{
return(string.Format(PreferredCulture, TimeResources.GetString("XMonthsAgo_2To4"), month.ToString(PreferredCulture)));
}
else if (month >= 5 && month <= 12)
{
return(string.Format(PreferredCulture, TimeResources.GetString("XMonthsAgo_5To12"), month.ToString(PreferredCulture)));
}
else
{
throw new ArgumentException(TimeResources.GetString("InvalidNumberOfMonths"));
}
}
/// <summary>
/// Returns a localized text string for the day of week.
/// </summary>
/// <param name="dow">Day of week.</param>
/// <returns>Localized text string.</returns>
private static string GetDayOfWeek(DayOfWeek dow)
{
string result;
switch (dow)
{
case DayOfWeek.Monday:
result = TimeResources.GetString("Monday");
break;
case DayOfWeek.Tuesday:
result = TimeResources.GetString("Tuesday");
break;
case DayOfWeek.Wednesday:
result = TimeResources.GetString("Wednesday");
break;
case DayOfWeek.Thursday:
result = TimeResources.GetString("Thursday");
break;
case DayOfWeek.Friday:
result = TimeResources.GetString("Friday");
break;
case DayOfWeek.Saturday:
result = TimeResources.GetString("Saturday");
break;
case DayOfWeek.Sunday:
result = TimeResources.GetString("Sunday");
break;
default:
result = TimeResources.GetString("Sunday");
break;
}
return(result);
}
/// <summary>
/// Converts a
/// <see cref="T:System.DateTime"/>
/// object into a string the represents the elapsed time
/// relatively to the present.
/// </summary>
/// <param name="value">The given date and time.</param>
/// <param name="targetType">
/// The type corresponding to the binding property, which must be of
/// <see cref="T:System.String"/>.
/// </param>
/// <param name="parameter">(Not used).</param>
/// <param name="culture">
/// The culture to use in the converter.
/// When not specified, the converter uses the current culture
/// as specified by the system locale.
/// </param>
/// <returns>The given date and time as a string.</returns>
public object Convert(object value, Type targetType, object parameter, string culture)
{
// Target value must be a System.DateTime object.
if (!(value is DateTime))
{
throw new ArgumentException(TimeResources.GetString("InvalidDateTimeArgument"));
}
string result;
DateTime given = ((DateTime)value).ToLocalTime();
DateTime current = DateTime.Now;
TimeSpan difference = current - given;
SetLocalizationCulture(PreferredCulture);
if (DateTimeFormatHelper.IsFutureDateTime(current, given))
{
// Future dates and times are not supported, but to prevent crashing an app
// if the time they receive from a server is slightly ahead of the phone's clock
// we'll just default to the minimum, which is "2 seconds ago".
result = GetPluralTimeUnits(2, PluralSecondStrings);
}
if (difference.TotalSeconds > Year)
{
// "over a year ago"
result = TimeResources.GetString("OverAYearAgo");
}
else if (difference.TotalSeconds > (1.5 * Month))
{
// "x months ago"
int nMonths = (int)((difference.TotalSeconds + Month / 2) / Month);
result = GetPluralMonth(nMonths);
}
else if (difference.TotalSeconds >= (3.5 * Week))
{
// "about a month ago"
result = TimeResources.GetString("AboutAMonthAgo");
}
else if (difference.TotalSeconds >= Week)
{
int nWeeks = (int)(difference.TotalSeconds / Week);
if (nWeeks > 1)
{
// "x weeks ago"
result = string.Format(PreferredCulture, TimeResources.GetString("XWeeksAgo_2To4"), nWeeks.ToString(PreferredCulture));
}
else
{
// "about a week ago"
result = TimeResources.GetString("AboutAWeekAgo");
}
}
else if (difference.TotalSeconds >= (5 * Day))
{
// "last <dayofweek>"
result = string.Format(PreferredCulture, TimeResources.GetString("LastDayOfWeek"), GetDayOfWeek(given.DayOfWeek));
}
else if (difference.TotalSeconds >= Day)
{
// "on <dayofweek>"
result = GetOnDayOfWeek(given.DayOfWeek);
}
else if (difference.TotalSeconds >= (2 * Hour))
{
// "x hours ago"
int nHours = (int)(difference.TotalSeconds / Hour);
result = GetPluralTimeUnits(nHours, PluralHourStrings);
}
else if (difference.TotalSeconds >= Hour)
{
// "about an hour ago"
result = TimeResources.GetString("AboutAnHourAgo");
}
else if (difference.TotalSeconds >= (2 * Minute))
{
// "x minutes ago"
int nMinutes = (int)(difference.TotalSeconds / Minute);
result = GetPluralTimeUnits(nMinutes, PluralMinuteStrings);
}
else if (difference.TotalSeconds >= Minute)
{
// "about a minute ago"
result = TimeResources.GetString("AboutAMinuteAgo");
}
else
{
// "x seconds ago" or default to "2 seconds ago" if less than two seconds.
int nSeconds = ((int)difference.TotalSeconds > 1.0) ? (int)difference.TotalSeconds : 2;
result = GetPluralTimeUnits(nSeconds, PluralSecondStrings);
}
return(result);
}