Metro style App Datetime formating.

Key Code:

1. Long and short Format

        private void Display_Click(object sender, RoutedEventArgs e)
        {
            // We keep results in this variable
            StringBuilder results = new StringBuilder();

            // Create basic date/time formatters.
            DateTimeFormatter[] basicFormatters = new[]
            {
                // Default date formatters
                new DateTimeFormatter("shortdate"),
                new DateTimeFormatter("longdate"),

                // Default time formatters
                new DateTimeFormatter("shorttime"),
                new DateTimeFormatter("longtime"),
             };

            // Create date/time to format and display.
            DateTime dateTime = DateTime.Now;

            // Try to format and display date/time if calendar supports it.
            foreach (DateTimeFormatter formatter in basicFormatters)
            {
                // Format and display date/time.
                results.AppendLine(formatter.Template + ": " + formatter.Format(dateTime));
            }
        }

2. Use different parameters.

        private void Display_Click2(object sender, RoutedEventArgs e)
        {
            // This scenario uses the Windows.Globalization.DateTimeFormatting.DateTimeFormatter class
            // to format a date/time by specifying a template via parameters.

            // We keep results in this variable
            StringBuilder results = new StringBuilder();

            // Create formatters with individual format specifiers for date/time elements.
            DateTimeFormatter[] templateFormatters = new[]
            {
                // Example formatters for dates.
                new DateTimeFormatter(
                    YearFormat.Full, 
                    MonthFormat.Abbreviated, 
                    DayFormat.Default, 
                    DayOfWeekFormat.Abbreviated),
                new DateTimeFormatter(
                    YearFormat.Abbreviated, 
                    MonthFormat.Abbreviated, 
                    DayFormat.Default, 
                    DayOfWeekFormat.None),
                new DateTimeFormatter(
                    YearFormat.Full, 
                    MonthFormat.Full, 
                    DayFormat.None, 
                    DayOfWeekFormat.None),
                new DateTimeFormatter(
                    YearFormat.None, 
                    MonthFormat.Full, 
                    DayFormat.Default, 
                    DayOfWeekFormat.None),

                // Example formatters for times.
                new DateTimeFormatter(
                    HourFormat.Default, 
                    MinuteFormat.Default, 
                    SecondFormat.Default),
                new DateTimeFormatter(
                    HourFormat.Default, 
                    MinuteFormat.Default, 
                    SecondFormat.None),
                new DateTimeFormatter(
                    HourFormat.Default, 
                    MinuteFormat.None, 
                    SecondFormat.None),
             };

            // Create date/time to format and display.
            DateTime dateTime = DateTime.Now;

            // Try to format and display date/time if calendar supports it.
            foreach (DateTimeFormatter formatter in templateFormatters)
            {
                // Format and display date/time.
                results.AppendLine(formatter.Template + ": " + formatter.Format(dateTime));
            }
        }

3. use String Template

        private void Display_Click3(object sender, RoutedEventArgs e)
        {
            // We keep results in this variable
            StringBuilder results = new StringBuilder();

            // Create template-based date/time formatters.
            DateTimeFormatter[] templateFormatters = new[]
            {
                // Formatters for dates.
                new DateTimeFormatter("day month"),
                new DateTimeFormatter("month year"),
                new DateTimeFormatter("day month year"),
                new DateTimeFormatter("dayofweek day month year"),
                new DateTimeFormatter("dayofweek.abbreviated"),
                new DateTimeFormatter("month.abbreviated"),
                new DateTimeFormatter("year.abbreviated"),

                // Formatters for time.
                new DateTimeFormatter("hour"),
                new DateTimeFormatter("hour minute"),
                new DateTimeFormatter("hour minute second"),
             };


            // Create date/time to format and display.
            DateTime dateTime = DateTime.Now;

            // Try to format and display date/time if calendar supports it.
            foreach (DateTimeFormatter formatter in templateFormatters)
            {
                // Format and display date/time.
                results.AppendLine(formatter.Template + ": " + formatter.Format(dateTime));
            }
        }

 C++ code

1 Long and short format

void App2::MainPage::Button_Click_1(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
	Array<DateTimeFormatter^> ^dateFormatters = {
		ref new DateTimeFormatter("shortdate"),
		ref new DateTimeFormatter("longdate"),
		ref new DateTimeFormatter("longtime")
	};

	Windows::Globalization::Calendar^ cal = ref new Windows::Globalization::Calendar();
	Windows::Foundation::DateTime dateToFormat = cal->GetDateTime();

	String^ results = "";

	for (unsigned int i = 0; i < dateFormatters->Length; i++)
	{
		results = results + dateFormatters[i]->Template + ": " + dateFormatters[i]->Format(dateToFormat) +"\n";
	}
}

2. Use different parameter

void App2::MainPage::Button_Click_2(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
    Array<DateTimeFormatter^> ^dateFormatters = {
		ref new DateTimeFormatter(
			YearFormat::Full, 
			MonthFormat::Abbreviated, 
			DayFormat::Default, 
			DayOfWeekFormat::Abbreviated),

		ref new DateTimeFormatter(
			YearFormat::Abbreviated, 
			MonthFormat::Abbreviated, 
			DayFormat::Default, 
			DayOfWeekFormat::None),

		ref new DateTimeFormatter(
			YearFormat::Full, 
			MonthFormat::Full, 
			DayFormat::None, 
			DayOfWeekFormat::None),

        ref new DateTimeFormatter(
			YearFormat::None, 
			MonthFormat::Full, 
			DayFormat::Default, 
			DayOfWeekFormat::None),

		ref new DateTimeFormatter(
			HourFormat::Default, 
			MinuteFormat::Default, 
			SecondFormat::Default),

		ref new DateTimeFormatter(
			HourFormat::Default, 
			MinuteFormat::Default, 
			SecondFormat::None),

		ref new DateTimeFormatter(
			HourFormat::Default, 
			MinuteFormat::None, 
			SecondFormat::None)
    };

	// Obtain the date that will be formatted.
	Windows::Globalization::Calendar^ cal = ref new Windows::Globalization::Calendar();
    Windows::Foundation::DateTime dateToFormat = cal->GetDateTime();
    
    // Keep the results here
    String^ results = "";

	// Generate the results.
    for (unsigned int i = 0; i < dateFormatters->Length; i++)
    {
        // Perform the actual formatting. 
        results = results + dateFormatters[i]->Template + ": " + dateFormatters[i]->Format(dateToFormat) + "\n"; 
    }
}

3.Use String Template

void App2::MainPage::Button_Click_3(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
	Array<DateTimeFormatter^> ^dateFormatters = {
		ref new DateTimeFormatter("month day"),
		ref new DateTimeFormatter("month year"),
		ref new DateTimeFormatter("month day year"),
		ref new DateTimeFormatter("month day dayofweek year"),
		ref new DateTimeFormatter("dayofweek.abbreviated"),
		ref new DateTimeFormatter("month.abbreviated"),
		ref new DateTimeFormatter("year.abbreviated"),
		ref new DateTimeFormatter("hour minute"),
		ref new DateTimeFormatter("hour minute second"),
		ref new DateTimeFormatter("hour")
	};

	// Obtain the date that will be formatted.
	Windows::Globalization::Calendar^ cal = ref new Windows::Globalization::Calendar();
	Windows::Foundation::DateTime dateToFormat = cal->GetDateTime();

	// Keep the results here
	String^ results = "";

	// Generate the results.
	for (unsigned int i = 0; i < dateFormatters->Length; i++)
	{
		results = results + dateFormatters[i]->Template + ": " + dateFormatters[i]->Format(dateToFormat) + "\n";
	}

}

From Metro style app samples.