DateTimeOffset.ToString Method (String, IFormatProvider)


The .NET API Reference documentation has a new home. Visit the .NET API Browser on to see the new experience.

Converts the value of the current DateTimeOffset object to its equivalent string representation using the specified format and culture-specific format information.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

public string ToString(
	string format,
	IFormatProvider formatProvider


Type: System.String

A format string.

Type: System.IFormatProvider

An object that supplies culture-specific formatting information.

Return Value

Type: System.String

A string representation of the value of the current DateTimeOffset object, as specified by format and provider.

Exception Condition

The length of format is one, and it is not one of the standard format specifier characters defined for DateTimeFormatInfo.


format does not contain a valid custom format pattern.


The date and time is outside the range of dates supported by the calendar used by formatProvider.

The format parameter should contain either a single format specifier character (see Standard Date and Time Format Strings) or a custom format pattern (see Custom Date and Time Format Strings). If format is a null or empty string (""), the DateTimeOffset object is output using the default format.

The following table shows the exact operation of certain format specifiers when used with DateTimeOffset, which differs from their behavior when used with DateTime.

Existing format specifier

New behavior


Designed to round-trip a date and time. With DateTimeOffset, maps to "zzz" (the offset is always displayed with hours and minutes). Note that "K" is a custom format specifier; it cannot appear as the single character in format.


Not supported.


Converts the DateTimeOffset object to Coordinated Universal Time (UTC) and outputs it using the custom format string ddd, dd MMM yyyy HH:mm:ss GMT.


Converts the DateTimeOffset value to UTC and outputs it using the format yyyy-MM-dd HH:mm:ssZ.

The remaining standard date and time format specifiers behave the same with the ToString(String) method as they do with the ToString method.

The pattern that corresponds to standard format specifiers, as well as the symbols and names of date and time components, is defined by the formatProvider parameter. The formatProvider parameter can be either of the following:

If formatProvider is null, the DateTimeFormatInfo object associated with the current culture is used (see CurrentCulture).

Notes to Callers:

The ToString(String, IFormatProvider) method returns the string representation of the date and time in the calendar used by the formatProvider parameter. Its calendar is defined by the Calendar property. If the value of the current DateTimeOffset instance is earlier than Calendar.MinSupportedDateTime or later than Calendar.MaxSupportedDateTime, the method throws an ArgumentOutOfRangeException. The following example provides an illustration. It attempts to format a date that is outside the range of the UmAlQuraCalendar class.

using System;
using System.Globalization;

public class Example
   public static void Main()
      CultureInfo arSA = new CultureInfo("ar-SA");
      arSA.DateTimeFormat.Calendar = new UmAlQuraCalendar(); 
      DateTimeOffset date1 = new DateTimeOffset(new DateTime(1890, 9, 10),

      try {
         Console.WriteLine(date1.ToString("d", arSA));
      catch (ArgumentOutOfRangeException) {
         Console.WriteLine("{0:d} is earlier than {1:d} or later than {2:d}", 
// The example displays the following output:
//    9/10/1890 is earlier than 4/30/1900 or later than 5/13/2029

The following example uses the ToString(String, IFormatProvider) method to display a DateTimeOffset object using a custom format string for several different cultures.

DateTimeOffset outputDate = new DateTimeOffset(2007, 11, 1, 9, 0, 0, 
                                     new TimeSpan(-7, 0, 0)); 
string format = "dddd, MMM dd yyyy HH:mm:ss zzz";

// Output date and time using custom format specification
Console.WriteLine(outputDate.ToString(format, null as DateTimeFormatInfo));
Console.WriteLine(outputDate.ToString(format, CultureInfo.InvariantCulture));
                                      new CultureInfo("fr-FR")));
                                      new CultureInfo("es-ES")));
// The example displays the following output to the console:
//    Thursday, Nov 01 2007 09:00:00 -07:00
//    Thursday, Nov 01 2007 09:00:00 -07:00
//    jeudi, nov. 01 2007 09:00:00 -07:00
//    jueves, nov 01 2007 09:00:00 -07:00

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top