/// <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);
}
