Ответ для Xamarin.iOS
using System;
namespace DateTimeFormat
{
class Program
{
static void Main(string[] args)
{
DateTime aDate = DateTime.Now;
Console.WriteLine(aDate.ToString("MM/dd/yyyy"));
Console.WriteLine(aDate.ToString("dddd, dd MMMM yyyy"));
Console.WriteLine(aDate.ToString("dddd, dd MMMM yyyy"));
Console.WriteLine(aDate.ToString("dddd, dd MMMM yyyy"));
Console.WriteLine(aDate.ToString("dddd, dd MMMM yyyy"));
Console.WriteLine(aDate.ToString("dddd, dd MMMM yyyy"));
Console.WriteLine(aDate.ToString("dddd, dd MMMM yyyy HH:mm:ss"));
Console.WriteLine(aDate.ToString("MM/dd/yyyy HH:mm"));
Console.WriteLine(aDate.ToString("MM/dd/yyyy hh:mm tt"));
Console.WriteLine(aDate.ToString("MM/dd/yyyy H:mm"));
Console.WriteLine(aDate.ToString("MM/dd/yyyy h:mm tt"));
Console.WriteLine(aDate.ToString("MM/dd/yyyy HH:mm:ss"));
Console.WriteLine(aDate.ToString("MMMM dd"));
Console.WriteLine(aDate.ToString("yyyy’-‘MM’-‘dd’T’HH’:’mm’:’ss.fffffffK"));
Console.WriteLine(aDate.ToString("ddd, dd MMM yyy HH’:’mm’:’ss ‘GMT’"));
Console.WriteLine(aDate.ToString("yyyy’-‘MM’-‘dd’T’HH’:’mm’:’ss"));
Console.WriteLine(aDate.ToString("HH:mm"));
Console.WriteLine(aDate.ToString("hh:mm tt"));
Console.WriteLine(aDate.ToString("H:mm"));
Console.WriteLine(aDate.ToString("h:mm tt"));
Console.WriteLine(aDate.ToString("HH:mm:ss"));
Console.WriteLine(aDate.ToString("yyyy MMMM"));
Console.ReadKey();
}
}
}
Мне приходилось писать все время и форматы в этом коде консоли.