ui::DateFormatSymbols¶

Header: winui/core/DateFormat.hpp.

The names and patterns a locale writes dates and times with, as the date and time controls use them. The defaults are the locale-independent ones: English names, Sunday first and US patterns.

A pattern uses the Windows date and time pattern letters, the way the Region settings write them:

• d and dd are the day, dd with a leading zero.
• ddd and dddd are the abbreviated and the full day name.
• M and MM are the month number, MM with a leading zero.
• MMM and MMMM are the abbreviated and the full month name.
• y and yy are the last two digits of the year, y without a leading zero.
• yyyy is the full year.
• h and hh are the hour on a 12-hour clock, H and HH on a 24-hour clock, doubled with a leading zero.
• m and mm are the minute.
• t is the first letter of the AM or PM designator, tt the whole designator.
• 'text' is written as it stands, and '' is one apostrophe.

Every other character is written as it is.

Example:

// A delivery date in German, written the same whatever the user's own locale is.
ui::DateFormatSymbols german = ui::DateFormatSymbols::invariant();
german.month_names = {"Januar", "Februar", "März", "April", "Mai", "Juni", "Juli", "August",
                      "September", "Oktober", "November", "Dezember"};
const std::chrono::year_month_day day{std::chrono::year{2026}, std::chrono::October, std::chrono::day{19}};
window.set_content(ui::Text{.text = "Lieferung am " + ui::format_date(day, "d. MMMM yyyy", german)}); // "19. Oktober 2026"

month_names¶

std::array<std::string, 12> month_names {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"}

The month names, January first.

abbreviated_month_names¶

std::array<std::string, 12> abbreviated_month_names {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}

The abbreviated month names, January first.

day_names¶

std::array<std::string, 7> day_names {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}

The day names, Sunday first (the index is std::chrono::weekday::c_encoding()).

abbreviated_day_names¶

std::array<std::string, 7> abbreviated_day_names {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}

The abbreviated day names, Sunday first.

shortest_day_names¶

std::array<std::string, 7> shortest_day_names {"Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"}

The shortest day names, Sunday first: a calendar's column headers.

first_day_of_week¶

std::chrono::weekday first_day_of_week = std::chrono::Sunday

The day a week starts on, the first column of a calendar.

short_date_pattern¶

std::string short_date_pattern = "M/d/yyyy"

The short date: "M/d/yyyy" (en-US), "dd.MM.yyyy" (de-DE), "yyyy-MM-dd" (sv-SE).

long_date_pattern¶

std::string long_date_pattern = "dddd, MMMM d, yyyy"

The long date: "dddd, MMMM d, yyyy" (en-US), "dddd, d. MMMM yyyy" (de-DE).

year_month_pattern¶

std::string year_month_pattern = "MMMM yyyy"

A month with its year, a calendar's heading: "MMMM yyyy" (en-US).

short_time_pattern¶

std::string short_time_pattern = "h:mm tt"

The short time: "h:mm tt" (en-US), "HH:mm" (de-DE).

am_designator¶

std::string am_designator = "AM"

The designators a 12-hour time carries: "AM" and "PM" (en-US), "vorm." and "nachm." (de-AT).

pm_designator¶

std::string pm_designator = "PM"

See am_designator.

twelve_hour_clock¶

bool twelve_hour_clock() const

Whether short_time_pattern uses the 12-hour clock (an h outside quotes).

invariant¶

static DateFormatSymbols invariant()

The locale-independent symbols, the default.