• Article

Standard Date and Time Format Strings

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Updated: October 2010

A standard date and time format string uses a single format specifier to define the text representation of a date and time value. Any date and time format string that contains more than one character, including white space, is interpreted as a custom date and time format string. For more information, see Custom Date and Time Format Strings. A standard or custom format string can be used in two ways:

  • To define the string that results from a formatting operation.

  • To define the text representation of a date and time value that can be converted to a DateTime or DateTimeOffset value by a parsing operation.

NoteNote:

Standard date and time format strings can be used with both DateTime and DateTimeOffset values.

The following table describes the standard date and time format specifiers. Unless otherwise noted, a particular standard date and time format specifier produces an identical string representation regardless of whether it is used with a DateTime or a DateTimeOffset value. See the Notes section for additional information about using standard date and time format strings.

Format specifier

Description

Examples

"d"

Short date pattern.

More information: The Short Date ("d") Format Specifier.

6/15/2009 1:45:30 PM -> 6/15/2009 (en-US)

6/15/2009 1:45:30 PM -> 15/06/2009 (fr-FR)

6/15/2009 1:45:30 PM -> 2009/06/15 (ja-JP)

"D"

Long date pattern.

More information: The Long Date ("D") Format Specifier.

6/15/2009 1:45:30 PM -> Monday, June 15, 2009 (en-US)

6/15/2009 1:45:30 PM -> 15 июня 2009 г. (ru-RU)

6/15/2009 1:45:30 PM -> Montag, 15. Juni 2009 (de-DE)

"f"

Full date/time pattern (short time).

More information: The Full Date Short Time ("f") Format Specifier.

6/15/2009 1:45:30 PM -> Monday, June 15, 2009 1:45 PM (en-US)

6/15/2009 1:45:30 PM -> den 15 juni 2009 13:45 (sv-SE)

6/15/2009 1:45:30 PM -> Δευτέρα, 15 Ιουνίου 2009 1:45 μμ (el-GR)

"F"

Full date/time pattern (long time).

More information: The Full Date Long Time ("F") Format Specifier.

6/15/2009 1:45:30 PM -> Monday, June 15, 2009 1:45:30 PM (en-US)

6/15/2009 1:45:30 PM -> den 15 juni 2009 13:45:30 (sv-SE)

6/15/2009 1:45:30 PM -> Δευτέρα, 15 Ιουνίου 2009 1:45:30 μμ (el-GR)

"g"

General date/time pattern (short time).

More information: The General Date Short Time ("g") Format Specifier.

6/15/2009 1:45:30 PM -> 6/15/2009 1:45 PM (en-US)

6/15/2009 1:45:30 PM -> 15/06/2009 13:45 (es-ES)

6/15/2009 1:45:30 PM -> 2009/6/15 13:45 (zh-CN)

"G"

General date/time pattern (long time).

More information: The General Date Long Time ("G") Format Specifier.

6/15/2009 1:45:30 PM -> 6/15/2009 1:45:30 PM (en-US)

6/15/2009 1:45:30 PM -> 15/06/2009 13:45:30 (es-ES)

6/15/2009 1:45:30 PM -> 2009/6/15 13:45:30 (zh-CN)

"M", "m"

Month/day pattern.

More information: The Month ("M", "m") Format Specifier.

6/15/2009 1:45:30 PM -> June 15 (en-US)

6/15/2009 1:45:30 PM -> 15. juni (da-DK)

6/15/2009 1:45:30 PM -> 15 Juni (id-ID)

"O", "o"

Round-trip date/time pattern.

More information: The Round-trip ("O", "o") Format Specifier.

6/15/2009 1:45:30 PM -> 2009-06-15T13:45:30.0900000

"R", "r"

RFC1123 pattern.

More information: The RFC1123 ("R", "r") Format Specifier.

6/15/2009 1:45:30 PM -> Mon, 15 Jun 2009 20:45:30 GMT

"s"

Sortable date/time pattern.

More information: The Sortable ("s") Format Specifier.

6/15/2009 1:45:30 PM -> 2009-06-15T13:45:30

"t"

Short time pattern.

More information: The Short Time ("t") Format Specifier.

6/15/2009 1:45:30 PM -> 1:45 PM (en-US)

6/15/2009 1:45:30 PM -> 13:45 (hr-HR)

6/15/2009 1:45:30 PM -> 01:45 م (ar-EG)

"T"

Long time pattern.

More information: The Long Time ("T") Format Specifier.

6/15/2009 1:45:30 PM -> 1:45:30 PM (en-US)

6/15/2009 1:45:30 PM -> 13:45:30 (hr-HR)

6/15/2009 1:45:30 PM -> 01:45:30 م (ar-EG)

"u"

Universal sortable date/time pattern.

More information: The Universal Sortable ("u") Format Specifier.

6/15/2009 1:45:30 PM -> 2009-06-15 20:45:30Z

"U"

Universal full date/time pattern.

More information: The Universal Full ("U") Format Specifier.

6/15/2009 1:45:30 PM -> Monday, June 15, 2009 8:45:30 PM (en-US)

6/15/2009 1:45:30 PM -> den 15 juni 2009 20:45:30 (sv-SE)

6/15/2009 1:45:30 PM -> Δευτέρα, 15 Ιουνίου 2009 8:45:30 μμ (el-GR)

"Y", "y"

Year month pattern.

More information: The Year Month ("Y") Format Specifier.

6/15/2009 1:45:30 PM -> June, 2009 (en-US)

6/15/2009 1:45:30 PM -> juni 2009 (da-DK)

6/15/2009 1:45:30 PM -> Juni 2009 (id-ID)

Any other single character

Unknown specifier.

Throws a run-time FormatException.

How Standard Format Strings Work

In a formatting operation, a standard format string is simply an alias for a custom format string. The advantage of using an alias to refer to a custom format string is that, although the alias remains invariant, the custom format string itself can vary. This is important because the string representations of date and time values typically vary by culture. For example, the "d" standard format string indicates that a date and time value is to be displayed using a short date pattern. For the invariant culture, this pattern is "MM/dd/yyyy". For the fr-FR culture, it is "dd/MM/yyyy". For the ja-JP culture, it is "yyyy/MM/dd".

If a standard format string in a formatting operation maps to a particular culture's custom format string, your application can define the specific culture whose custom format strings are used in one of these ways:

  • You can use the default (or current) culture. The following example displays a date using the current culture's short date format. In this case, the current culture is en-US.

    ' Display using current (en-us) culture's short date format
Dim thisDate As Date = #3/15/2008#
outputBlock.Text &= thisDate.ToString("d") & vbCrLf     ' Displays 3/15/2008

    // Display using current (en-us) culture's short date format
DateTime thisDate = new DateTime(2008, 3, 15);
outputBlock.Text += thisDate.ToString("d") + "\n";           // Displays 3/15/2008

  • You can pass a CultureInfo object representing the culture whose formatting is to be used to a method that has an IFormatProvider parameter. The following example displays a date using the short date format of the pt-BR culture.

    ' Display using pt-BR culture's short date format
Dim thisDate As Date = #3/15/2008#
Dim culture As New CultureInfo("pt-BR")
outputBlock.Text += String.Format(thisDate.ToString("d", culture)) & vbCrLf   ' Displays 15/3/2008

    // Display using pt-BR culture's short date format
DateTime thisDate = new DateTime(2008, 3, 15);
CultureInfo culture = new CultureInfo("pt-BR");
outputBlock.Text += String.Format(thisDate.ToString("d", culture)) + "\n";  // Displays 15/3/2008

  • You can pass a DateTimeFormatInfo object that provides formatting information to a method that has an IFormatProvider parameter. The following example displays a date using the short date format from a DateTimeFormatInfo object for the hr-HR culture.

    ' Display using date format information from hr-HR culture
Dim thisDate As Date = #3/15/2008#
Dim fmt As DateTimeFormatInfo = (New CultureInfo("hr-HR")).DateTimeFormat
outputBlock.Text += String.Format(thisDate.ToString("d", fmt)) & vbCrLf   ' Displays 15.3.2008

    // Display using date format information from hr-HR culture
DateTime thisDate = new DateTime(2008, 3, 15);
DateTimeFormatInfo fmt = (new CultureInfo("hr-HR")).DateTimeFormat;
outputBlock.Text += String.Format(thisDate.ToString("d", fmt)) + "\n";      // Displays 15.3.2008

In some cases, the standard format string serves as a convenient abbreviation for a longer custom format string that is invariant. Four standard format strings fall into this category: "O" (or "o"), "R" (or "r"), "s", and "u". These strings correspond to custom format strings defined by the invariant culture. They produce string representations of date and time values that are intended to be identical across cultures. The following table provides information on these four standard date and time format strings.

Standard format string

Defined by DateTimeFormatInfo.InvariantInfo property

Custom format string

"O" or "o"

None

yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffzz

"R" or "r"

RFC1123Pattern

ddd, dd MMM yyyy HH':'mm':'ss 'GMT'

"s"

SortableDateTimePattern

yyyy'-'MM'-'dd'T'HH':'mm':'ss

"u"

UniversalSortableDateTimePattern

yyyy'-'MM'-'dd HH':'mm':'ss'Z'

Standard format strings can also be used in parsing operations with the DateTime.ParseExact or DateTimeOffset.ParseExact methods, which require an input string to exactly conform to a particular pattern for the parse operation to succeed. Many standard format strings map to multiple custom format strings, so a date and time value can be represented in a variety of formats and the parse operation will still succeed.

The following sections describe the standard format specifiers for DateTime and DateTimeOffset values.

The Short Date ("d") Format Specifier

The "d" standard format specifier represents a custom date and time format string that is defined by a specific culture's DateTimeFormatInfo.ShortDatePattern property. For example, the custom format string that is returned by the ShortDatePattern property of the invariant culture is "MM/dd/yyyy".

The following table lists the DateTimeFormatInfo object properties that control the formatting of the returned string.

Property

Description

ShortDatePattern

Defines the overall format of the result string.

The following example uses the "d" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008#
outputBlock.Text &= String.Format(date1.ToString("d", DateTimeFormatInfo.InvariantInfo)) & vbCrLf
' Displays 04/10/2008
outputBlock.Text &= date1.ToString("d", _
                  New CultureInfo("en-US")) & vbCrLf
' Displays 4/10/2008                       
outputBlock.Text &= date1.ToString("d", _
                  New CultureInfo("en-NZ")) & vbCrLf
' Displays 10/04/2008                       
outputBlock.Text &= date1.ToString("d", _
                  New CultureInfo("de-DE")) & vbCrLf
' Displays 10.04.2008                       

DateTime date1 = new DateTime(2008, 4, 10);
outputBlock.Text += String.Format(date1.ToString("d", DateTimeFormatInfo.InvariantInfo)) + "\n";
// Displays 04/10/2008
outputBlock.Text += date1.ToString("d",
                  new CultureInfo("en-US")) + "\n";
// Displays 4/10/2008                       
outputBlock.Text += date1.ToString("d",
                  new CultureInfo("en-NZ")) + "\n";
// Displays 10/04/2008                       
outputBlock.Text += date1.ToString("d",
                  new CultureInfo("de-DE")) + "\n";
// Displays 10.04.2008

Back to table

The Long Date ("D") Format Specifier

The "D" standard format specifier represents a custom date and time format string that is defined by the current DateTimeFormatInfo.LongDatePattern property. For example, the custom format string for the invariant culture is "dddd, dd MMMM yyyy".

The following table lists the properties of the DateTimeFormatInfo object that control the formatting of the returned string.

Property

Description

LongDatePattern

Defines the overall format of the result string.

DayNames

Defines the localized day names that can appear in the result string.

MonthNames

Defines the localized month names that can appear in the result string.

The following example uses the "D" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008#
outputBlock.Text &= date1.ToString("D", _
                  New CultureInfo("en-US")) & vbCrLf
' Displays Thursday, April 10, 2008                        
outputBlock.Text &= date1.ToString("D", _
                  New CultureInfo("pt-BR")) & vbCrLf
' Displays quinta-feira, 10 de abril de 2008                        
outputBlock.Text &= date1.ToString("D", _
                  New CultureInfo("es-MX")) & vbCrLf
' Displays jueves, 10 de abril de 2008                        

DateTime date1 = new DateTime(2008, 4, 10);
outputBlock.Text += date1.ToString("D",
                  new CultureInfo("en-US")) + "\n";
// Displays Thursday, April 10, 2008                        
outputBlock.Text += date1.ToString("D",
                  new CultureInfo("pt-BR")) + "\n";
// Displays quinta-feira, 10 de abril de 2008                        
outputBlock.Text += date1.ToString("D",
                  new CultureInfo("es-MX")) + "\n";
// Displays jueves, 10 de abril de 2008

Back to table

The Full Date Short Time ("f") Format Specifier

The "f" standard format specifier represents a combination of the long date ("D") and short time ("t") patterns, separated by a space.

The result string is affected by the formatting information of a specific DateTimeFormatInfo object. The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier returned by the DateTimeFormatInfo.LongDatePattern and DateTimeFormatInfo.ShortTimePattern properties of some cultures may not make use of all properties.

Property

Description

LongDatePattern

Defines the format of the date component of the result string.

ShortTimePattern

Defines the format of the time component of the result string.

DayNames

Defines the localized day names that can appear in the result string.

MonthNames

Defines the localized month names that can appear in the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The following example uses the "f" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("f", _
                  New CultureInfo("en-US")) & vbCrLf
' Displays Thursday, April 10, 2008 6:30 AM                        
outputBlock.Text &= date1.ToString("f", _
                  New CultureInfo("fr-FR")) & vbCrLf
' Displays jeudi 10 avril 2008 06:30                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("f",
                  new CultureInfo("en-US")) + "\n";
// Displays Thursday, April 10, 2008 6:30 AM                        
outputBlock.Text += date1.ToString("f",
                  new CultureInfo("fr-FR")) + "\n";
// Displays jeudi 10 avril 2008 06:30

Back to table

The Full Date Long Time ("F") Format Specifier

The "F" standard format specifier represents a custom date and time format string that is defined by the current DateTimeFormatInfo.FullDateTimePattern property. For example, the custom format string for the invariant culture is "dddd, dd MMMM yyyy HH:mm:ss".

The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier that is returned by the FullDateTimePattern property of some cultures may not make use of all properties.

Property

Description

FullDateTimePattern

Defines the overall format of the result string.

DayNames

Defines the localized day names that can appear in the result string.

MonthNames

Defines the localized month names that can appear in the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The following example uses the "F" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("F", _
                  New CultureInfo("en-US")) & vbCrLf
' Displays Thursday, April 10, 2008 6:30:00 AM                        
outputBlock.Text &= date1.ToString("F", _
                  New CultureInfo("fr-FR")) & vbCrLf
' Displays jeudi 10 avril 2008 06:30:00                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("F",
                  new CultureInfo("en-US")) + "\n";
// Displays Thursday, April 10, 2008 6:30:00 AM                        
outputBlock.Text += date1.ToString("F",
                  new CultureInfo("fr-FR")) + "\n";
// Displays jeudi 10 avril 2008 06:30:00

Back to table

The General Date Short Time ("g") Format Specifier

The "g" standard format specifier represents a combination of the short date ("d") and short time ("t") patterns, separated by a space.

The result string is affected by the formatting information of a specific DateTimeFormatInfo object. The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier that is returned by the DateTimeFormatInfo.ShortDatePattern and DateTimeFormatInfo.ShortTimePattern properties of some cultures may not make use of all properties.

Property

Description

ShortDatePattern

Defines the format of the date component of the result string.

ShortTimePattern

Defines the format of the time component of the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The following example uses the "g" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("g", _
                  DateTimeFormatInfo.InvariantInfo) & vbCrLf
' Displays 04/10/2008 06:30                      
outputBlock.Text &= date1.ToString("g", _
                  New CultureInfo("en-us")) & vbCrLf
' Displays 4/10/2008 6:30 AM                       
outputBlock.Text &= date1.ToString("g", _
                  New CultureInfo("fr-BE")) & vbCrLf
' Displays10/04/2008 6:30                        

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("g",
                  DateTimeFormatInfo.InvariantInfo) + "\n";
// Displays 04/10/2008 06:30                      
outputBlock.Text += date1.ToString("g",
                  new CultureInfo("en-us")) + "\n";
// Displays 4/10/2008 6:30 AM                       
outputBlock.Text += date1.ToString("g",
                  new CultureInfo("fr-BE")) + "\n";
// Displays10/04/2008 6:30

Back to table

The General Date Long Time ("G") Format Specifier

The "G" standard format specifier represents a combination of the short date ("d") and long time ("T") patterns, separated by a space.

The result string is affected by the formatting information of a specific DateTimeFormatInfo object. The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier that is returned by the DateTimeFormatInfo.ShortDatePattern and DateTimeFormatInfo.LongTimePattern properties of some cultures may not make use of all properties.

Property

Description

ShortDatePattern

Defines the format of the date component of the result string.

LongTimePattern

Defines the format of the time component of the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The following example uses the "G" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("G", _
                  DateTimeFormatInfo.InvariantInfo) & vbCrLf
' Displays 04/10/2008 06:30:00
outputBlock.Text &= date1.ToString("G", _
                  New CultureInfo("en-us")) & vbCrLf
' Displays 4/10/2008 6:30:00 AM                        
outputBlock.Text &= date1.ToString("G", _
                  New CultureInfo("nl-BE")) & vbCrLf
' Displays 10/04/2008 6:30:00                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("G",
                  DateTimeFormatInfo.InvariantInfo) + "\n";
// Displays 04/10/2008 06:30:00
outputBlock.Text += date1.ToString("G",
                  new CultureInfo("en-us")) + "\n";
// Displays 4/10/2008 6:30:00 AM                        
outputBlock.Text += date1.ToString("G",
                  new CultureInfo("nl-BE")) + "\n";
// Displays 10/04/2008 6:30:00

Back to table

The Month ("M", "m") Format Specifier

The "M" or "m" standard format specifier represents a custom date and time format string that is defined by the current DateTimeFormatInfo.MonthDayPattern property. For example, the custom format string for the invariant culture is "MMMM dd".

The following table lists the DateTimeFormatInfo object properties that control the formatting of the returned string.

Property

Description

MonthDayPattern

Defines the overall format of the result string.

MonthNames

Defines the localized month names that can appear in the result string.

The following example uses the "m" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("m", _
                  New CultureInfo("en-us")) & vbCrLf
' Displays April 10                        
outputBlock.Text &= date1.ToString("m", _
                  New CultureInfo("ms-MY")) & vbCrLf
' Displays 10 April                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("m",
                  new CultureInfo("en-us")) + "\n";
// Displays April 10                        
outputBlock.Text += date1.ToString("m",
                  new CultureInfo("ms-MY")) + "\n";
// Displays 10 April

Back to table

The Round-trip ("O", "o") Format Specifier

The "O" or "o" standard format specifier represents a custom date and time format string using a pattern that preserves time zone information. For DateTime values, this format specifier is designed to preserve date and time values along with the DateTime.Kind property in text. The formatted string can be parsed back by using the DateTime.Parse(String, IFormatProvider, DateTimeStyles) or DateTime.ParseExact method if the styles parameter is set to DateTimeStyles.RoundtripKind.

The "O" or "o" standard format specifier corresponds to the "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffK" custom format string for DateTime values and to the "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffffffzzz" custom format string for DateTimeOffset values. In this string, the pairs of single quotation marks that delimit individual characters, such as the hyphens, the colons, and the letter "T", indicate that the individual character is a literal that cannot be changed. The apostrophes do not appear in the output string.

The pattern for this specifier reflects a defined standard (ISO 8601). Therefore, it is always the same regardless of the culture used or the format provider supplied. Strings that are passed to the Parse or ParseExact method must conform exactly to this custom format pattern, or a FormatException is thrown.

When this standard format specifier is used, the formatting or parsing operation always uses the invariant culture.

The following example uses the "o" format specifier to display a DateTime and a DateTimeOffset value on a system in the U.S. Pacific Time zone.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
Dim dateOffset As New DateTimeOffset(date1, TimeZoneInfo.Local.GetUtcOffset(date1))
outputBlock.Text &= date1.ToString("o") & vbCrLf
' Displays 2008-04-10T06:30:00.0000000                        
outputBlock.Text &= dateOffset.ToString("o") & vbCrLf
' Displays 2008-04-10T06:30:00.0000000-07:00                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
DateTimeOffset dateOffset = new DateTimeOffset(date1,
                            TimeZoneInfo.Local.GetUtcOffset(date1));
outputBlock.Text += date1.ToString("o") + "\n";
// Displays 2008-04-10T06:30:00.0000000                        
outputBlock.Text += dateOffset.ToString("o") + "\n";
// Displays 2008-04-10T06:30:00.0000000-07:00

The following example uses the "o" format specifier to create a formatted string, and then restores the original date and time value by calling a date and time Parse method.

' Round-trip DateTime values.
Dim originalDate, newDate As Date
Dim dateString As String
' Round-trip a local time.
originalDate = Date.SpecifyKind(#4/10/2008 6:30AM#, DateTimeKind.Local)
dateString = originalDate.ToString("o")
newDate = Date.Parse(dateString, Nothing, DateTimeStyles.RoundtripKind)
outputBlock.Text += String.Format("Round-tripped {0} {1} to {2} {3}.", originalDate, originalDate.Kind, _
                                  newDate, newDate.Kind) + vbCrLf
' Round-trip a UTC time.
originalDate = Date.SpecifyKind(#4/12/2008 9:30AM#, DateTimeKind.Utc)                  
dateString = originalDate.ToString("o")
newDate = Date.Parse(dateString, Nothing, DateTimeStyles.RoundtripKind)
outputBlock.Text += String.Format("Round-tripped {0} {1} to {2} {3}.", originalDate, originalDate.Kind, _
                                  newDate, newDate.Kind) + vbCrLf
' Round-trip time in an unspecified time zone.
originalDate = Date.SpecifyKind(#4/13/2008 12:30PM#, DateTimeKind.Unspecified)                  
dateString = originalDate.ToString("o")
newDate = Date.Parse(dateString, Nothing, DateTimeStyles.RoundtripKind)
outputBlock.Text += String.Format("Round-tripped {0} {1} to {2} {3}.", originalDate, originalDate.Kind, _
                                  newDate, newDate.Kind) + vbCrLf

' Round-trip a DateTimeOffset value.
Dim originalDTO As New DateTimeOffset(#4/12/2008 9:30AM#, New TimeSpan(-8, 0, 0))
dateString = originalDTO.ToString("o")
Dim newDTO As DateTimeOffset = DateTimeOffset.Parse(dateString, Nothing, DateTimeStyles.RoundtripKind)
outputBlock.Text += String.Format("Round-tripped {0} to {1}.", originalDTO, newDTO) + vbCrLf
' The example displays the following output:
'    Round-tripped 4/10/2008 6:30:00 AM Local to 4/10/2008 6:30:00 AM Local.
'    Round-tripped 4/12/2008 9:30:00 AM Utc to 4/12/2008 9:30:00 AM Utc.
'    Round-tripped 4/13/2008 12:30:00 PM Unspecified to 4/13/2008 12:30:00 PM Unspecified.
'    Round-tripped 4/12/2008 9:30:00 AM -08:00 to 4/12/2008 9:30:00 AM -08:00.

// Round-trip DateTime values.
DateTime originalDate, newDate;
string dateString;
// Round-trip a local time.
originalDate = DateTime.SpecifyKind(new DateTime(2008, 4, 10, 6, 30, 0), DateTimeKind.Local);
dateString = originalDate.ToString("o");
newDate = DateTime.Parse(dateString, null, DateTimeStyles.RoundtripKind);
outputBlock.Text += String.Format("Round-tripped {0} {1} to {2} {3}.\n", originalDate, originalDate.Kind, 
                                  newDate, newDate.Kind);
// Round-trip a UTC time.
originalDate = DateTime.SpecifyKind(new DateTime(2008, 4, 12, 9, 30, 0), DateTimeKind.Utc);                  
dateString = originalDate.ToString("o");
newDate = DateTime.Parse(dateString, null, DateTimeStyles.RoundtripKind);
outputBlock.Text += String.Format("Round-tripped {0} {1} to {2} {3}.\n", originalDate, originalDate.Kind, 
                                  newDate, newDate.Kind);
// Round-trip time in an unspecified time zone.
originalDate = DateTime.SpecifyKind(new DateTime(2008, 4, 13, 12, 30, 0), DateTimeKind.Unspecified);                  
dateString = originalDate.ToString("o");
newDate = DateTime.Parse(dateString, null, DateTimeStyles.RoundtripKind);
outputBlock.Text += String.Format("Round-tripped {0} {1} to {2} {3}.\n", originalDate, originalDate.Kind, 
                                  newDate, newDate.Kind);

// Round-trip a DateTimeOffset value.
DateTimeOffset originalDTO = new DateTimeOffset(2008, 4, 12, 9, 30, 0, new TimeSpan(-8, 0, 0));
dateString = originalDTO.ToString("o");
DateTimeOffset newDTO = DateTimeOffset.Parse(dateString, null, DateTimeStyles.RoundtripKind);
outputBlock.Text += String.Format("Round-tripped {0} to {1}.\n", originalDTO, newDTO);
// The example displays the following output:
//    Round-tripped 4/10/2008 6:30:00 AM Local to 4/10/2008 6:30:00 AM Local.
//    Round-tripped 4/12/2008 9:30:00 AM Utc to 4/12/2008 9:30:00 AM Utc.
//    Round-tripped 4/13/2008 12:30:00 PM Unspecified to 4/13/2008 12:30:00 PM Unspecified.
//    Round-tripped 4/12/2008 9:30:00 AM -08:00 to 4/12/2008 9:30:00 AM -08:00.

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The RFC1123 ("R", "r") Format Specifier

The "R" or "r" standard format specifier represents a custom date and time format string that is defined by the DateTimeFormatInfo.RFC1123Pattern property. The pattern reflects a defined standard, and the property is read-only. Therefore, it is always the same, regardless of the culture used or the format provider supplied. The custom format string is "ddd, dd MMM yyyy HH':'mm':'ss 'GMT'". When this standard format specifier is used, the formatting or parsing operation always uses the invariant culture.

The result string is affected by the following properties of the DateTimeFormatInfo object returned by the DateTimeFormatInfo.InvariantInfo property that represents the invariant culture.

Property

Description

RFC1123Pattern

Defines the format of the result string.

AbbreviatedDayNames

Defines the abbreviated day names that can appear in the result string.

AbbreviatedMonthNames

Defines the abbreviated month names that can appear in the result string.

Although the RFC 1123 standard expresses a time as Coordinated Universal Time (UTC), the formatting operation does not modify the value of the DateTime or DateTimeOffset object that is being formatted. Therefore, the application must convert the date and time value to UTC before it performs the formatting operation. To perform this conversion, DateTime values can call the DateTime.ToUniversalTime method, and DateTimeOffset values can call the ToUniversalTime method.

The following example uses the "r" format specifier to display a DateTime and a DateTimeOffset value on a system in the U.S. Pacific Time zone.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
Dim dateOffset As New DateTimeOffset(date1, TimeZoneInfo.Local.GetUtcOffset(date1))
outputBlock.Text &= date1.ToUniversalTime.ToString("r") & vbCrLf
' Displays Thu, 10 Apr 2008 13:30:00 GMT                       
outputBlock.Text &= dateOffset.ToUniversalTime.ToString("r") & vbCrLf
' Displays Thu, 10 Apr 2008 13:30:00 GMT                        

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
DateTimeOffset dateOffset = new DateTimeOffset(date1,
                            TimeZoneInfo.Local.GetUtcOffset(date1));
outputBlock.Text += date1.ToUniversalTime().ToString("r") + "\n";
// Displays Thu, 10 Apr 2008 13:30:00 GMT                       
outputBlock.Text += dateOffset.ToUniversalTime().ToString("r") + "\n";
// Displays Thu, 10 Apr 2008 13:30:00 GMT

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The Sortable ("s") Format Specifier

The "s" standard format specifier represents a custom date and time format string that is defined by the DateTimeFormatInfo.SortableDateTimePattern property. The pattern reflects a defined standard (ISO 8601), and the property is read-only. Therefore, it is always the same, regardless of the culture used or the format provider supplied. The custom format string is "yyyy'-'MM'-'dd'T'HH':'mm':'ss".

When this standard format specifier is used, the formatting or parsing operation always uses the invariant culture.

The following example uses the "s" format specifier to display a DateTime and a DateTimeOffset value on a system in the U.S. Pacific Time zone.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("s") & vbCrLf
' Displays 2008-04-10T06:30:00                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("s") + "\n";
// Displays 2008-04-10T06:30:00

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The Short Time ("t") Format Specifier

The "t" standard format specifier represents a custom date and time format string that is defined by the current DateTimeFormatInfo.ShortTimePattern property. For example, the custom format string for the invariant culture is "HH:mm".

The result string is affected by the formatting information of a specific DateTimeFormatInfo object. The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier that is returned by the DateTimeFormatInfo.ShortTimePattern property of some cultures may not make use of all properties.

Property

Description

ShortTimePattern

Defines the format of the time component of the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The following example uses the "t" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("t", _
                  New CultureInfo("en-us")) & vbCrLf
' Displays 6:30 AM                        
outputBlock.Text &= date1.ToString("t", _
                  New CultureInfo("es-ES")) & vbCrLf
' Displays 6:30                      

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("t",
                  new CultureInfo("en-us")) + "\n";
// Displays 6:30 AM                        
outputBlock.Text += date1.ToString("t",
                  new CultureInfo("es-ES")) + "\n";
// Displays 6:30

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The Long Time ("T") Format Specifier

The "T" standard format specifier represents a custom date and time format string that is defined by a specific culture's DateTimeFormatInfo.LongTimePattern property. For example, the custom format string for the invariant culture is "HH:mm:ss".

The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier that is returned by the DateTimeFormatInfo.LongTimePattern property of some cultures may not make use of all properties.

Property

Description

LongTimePattern

Defines the format of the time component of the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The following example uses the "T" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToString("T", _
                  New CultureInfo("en-us")) & vbCrLf
' Displays 6:30:00 AM                       
outputBlock.Text &= date1.ToString("T", _
                  New CultureInfo("es-ES")) & vbCrLf
' Displays 6:30:00                      

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("T",
                  new CultureInfo("en-us")) + "\n";
// Displays 6:30:00 AM                       
outputBlock.Text += date1.ToString("T",
                  new CultureInfo("es-ES")) + "\n";
// Displays 6:30:00

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The Universal Sortable ("u") Format Specifier

The "u" standard format specifier represents a custom date and time format string that is defined by the DateTimeFormatInfo.UniversalSortableDateTimePattern property. The pattern reflects a defined standard, and the property is read-only. Therefore, it is always the same, regardless of the culture used or the format provider supplied. The custom format string is "yyyy'-'MM'-'dd HH':'mm':'ss'Z'". When this standard format specifier is used, the formatting or parsing operation always uses the invariant culture.

Although the result string should express a time as Coordinated Universal Time (UTC), no conversion of the original DateTime or DateTimeOffset value is performed during the formatting operation. Therefore, the application must convert the date and time value to UTC before formatting it. To perform this conversion, DateTime values can call the DateTime.ToUniversalTime method, and DateTimeOffset values can call the ToUniversalTime method

The following example uses the "u" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= date1.ToUniversalTime.ToString("u") & vbCrLf
' Displays 2008-04-10 13:30:00Z                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToUniversalTime().ToString("u") + "\n";
// Displays 2008-04-10 13:30:00Z

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The Universal Full ("U") Format Specifier

The "U" standard format specifier represents a custom date and time format string that is defined by a specified culture's DateTimeFormatInfo.FullDateTimePattern property. The pattern is the same as the "F" pattern. However, the DateTime value is automatically converted to UTC before it is formatted.

The following table lists the DateTimeFormatInfo object properties that may control the formatting of the returned string. The custom format specifier that is returned by the FullDateTimePattern property of some cultures may not make use of all properties.

Property

Description

FullDateTimePattern

Defines the overall format of the result string.

DayNames

Defines the localized day names that can appear in the result string.

MonthNames

Defines the localized month names that can appear in the result string.

AMDesignator

Defines the string that indicates times from midnight to before noon in a 12-hour clock.

PMDesignator

Defines the string that indicates times from noon to before midnight in a 12-hour clock.

The "U" format specifier is not supported by the DateTimeOffset type and throws a FormatException if it is used to format a DateTimeOffset value.

The following example uses the "U" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= String.Format(date1.ToString("U", New CultureInfo("en-US"))) & vbCrLf
' Displays Thursday, April 10, 2008 1:30:00 PM                       
outputBlock.Text &= String.Format(date1.ToString("U", New CultureInfo("sv-FI"))) & vbCrLf
' Displays den 10 april 2008 13:30:00                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("U",
                  new CultureInfo("en-US")) + "\n";
// Displays Thursday, April 10, 2008 1:30:00 PM                       
outputBlock.Text += date1.ToString("U",
                  new CultureInfo("sv-FI")) + "\n";
// Displays den 10 april 2008 13:30:00

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The Year Month ("Y", "y") Format Specifier

The "Y" or "y" standard format specifier represents a custom date and time format string that is defined by the DateTimeFormatInfo.YearMonthPattern property of a specified culture. For example, the custom format string for the invariant culture is "yyyy MMMM".

The following table lists the DateTimeFormatInfo object properties that control the formatting of the returned string.

Property

Description

YearMonthPattern

Defines the overall format of the result string.

MonthNames

Defines the localized month names that can appear in the result string.

The following example uses the "y" format specifier to display a date and time value.

Dim date1 As Date = #4/10/2008 6:30:00 AM#
outputBlock.Text &= String.Format(date1.ToString("Y", New CultureInfo("en-US"))) & vbCrLf
' Displays April, 2008                       
outputBlock.Text &= String.Format(date1.ToString("y", New CultureInfo("af-ZA"))) & vbCrLf
' Displays April 2008                       

DateTime date1 = new DateTime(2008, 4, 10, 6, 30, 0);
outputBlock.Text += date1.ToString("Y",
                  new CultureInfo("en-US")) + "\n";
// Displays April, 2008                       
outputBlock.Text += date1.ToString("y",
                  new CultureInfo("af-ZA")) + "\n";
// Displays April 2008

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Notes

Control Panel Settings

The settings in the Regional and Language Options item in Control Panel influence the result string produced by a formatting operation. These settings are used to initialize the DateTimeFormatInfo object associated with the current thread culture, which provides values used to govern formatting. Computers that use different settings generate different result strings.

In addition, if the CultureInfo.CultureInfo(String) constructor is used to instantiate a new CultureInfo object that represents the same culture as the current system culture, any user customizations will be reflected in the new CultureInfo object.

DateTimeFormatInfo Properties

Formatting is influenced by properties of the current DateTimeFormatInfo object, which is provided implicitly by the current thread culture or explicitly by the IFormatProvider parameter of the method that invokes formatting. For the IFormatProvider parameter, your application should specify a CultureInfo object, which represents a culture, or a DateTimeFormatInfo object, which represents a particular culture's date and time formatting conventions. Many of the standard date and time format specifiers are aliases for formatting patterns defined by properties of the current DateTimeFormatInfo object. Your application can change the result produced by some standard date and time format specifiers by changing the corresponding date and time format patterns of the corresponding DateTimeFormatInfo property.

Change History

Date

History

Reason

October 2010

Added information about standard format strings in parsing operations.

Customer feedback.