DateTimeFormatInfo.GetAllDateTimePatterns Method (Char)

 

Returns all the patterns in which date and time values can be formatted using the specified standard format string.

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

Public Function GetAllDateTimePatterns (
	format As Char
) As String()

Parameters

format
Type: System.Char

A standard format string.

Return Value

Type: System.String()

An array containing the standard patterns in which date and time values can be formatted using the specified format string.

Exception Condition
ArgumentException

format is not a valid standard format string.

This method returns an array containing the custom format strings that correspond to a particular standard format string. See Standard Date and Time Format Strings for a list of the standard format strings.

You can use the custom format strings in the array returned by the GetAllDateTimePatterns method in formatting operations. However, if you do, the string representation of a date and time value returned in that formatting operation cannot always be parsed successfully by the Parse and TryParse methods. Therefore, you cannot assume that the custom format strings returned by the GetAllDateTimePatterns method can be used to round-trip date and time values. The following example illustrates this problem. It retrieves a DateTimeFormatInfo object that contains formatting information for the Russia (Russian) culture. It calls the GetAllDateTimePatterns(Char) method for each standard format string, and then passes each custom format string in the returned array to the DateTime.ToString(String) method to create the string representation of a date and time. This example then attempts to parse this value by calling the DateTime.TryParse(String, DateTime) method. As the output from the example shows, some of the custom format strings do not produce a date and time value that successfully round-trips.

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim culture As CultureInfo = CultureInfo.CreateSpecificCulture("ru-RU")
      Dim formats() As String = { "d", "D", "f", "F", "g", "G", "m",
                                  "o", "r", "s", "t", "T", "u", "U", "y" }
      Dim date1 = New DateTime(2011, 02, 01, 7, 30, 45, 0)
      Dim date2 As DateTime
      Dim total, noRoundTrip As Integer

      For Each fmt In formats
         total = 0 : noRoundTrip = 0
         For Each pattern In culture.DateTimeFormat.GetAllDateTimePatterns(CChar(fmt))
            total += 1
            If Not DateTime.TryParse(date1.ToString(pattern), date2)
               noRoundTrip += 1
               Console.WriteLine("Unable to parse {0:" + pattern + "} (format '{1}')", 
                                 date1, pattern)
            End If             
         Next
         If noRoundTrip > 0 Then
            Console.WriteLine("{0}: Unable to round-trip {1} of {2} format strings.",
                              fmt, noRoundTrip, total)
            Console.WriteLine()
         Else
            Console.WriteLine("{0}: All custom format strings round trip.", fmt)
            Console.WriteLine()
         End If
      Next
   End Sub
End Module
' The example displays the following output:
'    d: All custom format strings round trip.
'    
'    Unable to parse 1 February 2011 г. (format 'd MMMM yyyy 'г.'')
'    Unable to parse 01 February 2011 г. (format 'dd MMMM yyyy 'г.'')
'    D: Unable to round-trip 2 of 2 format strings.
'    
'    Unable to parse 1 February 2011 г. 7:30 (format 'd MMMM yyyy 'г.' H:mm')
'    Unable to parse 1 February 2011 г. 07:30 (format 'd MMMM yyyy 'г.' HH:mm')
'    Unable to parse 01 February 2011 г. 7:30 (format 'dd MMMM yyyy 'г.' H:mm')
'    Unable to parse 01 February 2011 г. 07:30 (format 'dd MMMM yyyy 'г.' HH:mm')
'    f: Unable to round-trip 4 of 4 format strings.
'    
'    Unable to parse 1 February 2011 г. 7:30:45 (format 'd MMMM yyyy 'г.' H:mm:ss')
'    Unable to parse 1 February 2011 г. 07:30:45 (format 'd MMMM yyyy 'г.' HH:mm:ss')
'    Unable to parse 01 February 2011 г. 7:30:45 (format 'dd MMMM yyyy 'г.' H:mm:ss')
'    Unable to parse 01 February 2011 г. 07:30:45 (format 'dd MMMM yyyy 'г.' HH:mm:ss')
'    F: Unable to round-trip 4 of 4 format strings.
'    
'    g: All custom format strings round trip.
'    
'    G: All custom format strings round trip.
'    
'    m: All custom format strings round trip.
'    
'    o: All custom format strings round trip.
'    
'    r: All custom format strings round trip.
'    
'    s: All custom format strings round trip.
'    
'    t: All custom format strings round trip.
'    
'    T: All custom format strings round trip.
'    
'    u: All custom format strings round trip.
'    
'    Unable to parse 1 February 2011 г. 7:30:45 (format 'd MMMM yyyy 'г.' H:mm:ss')
'    Unable to parse 1 February 2011 г. 07:30:45 (format 'd MMMM yyyy 'г.' HH:mm:ss')
'    Unable to parse 01 February 2011 г. 7:30:45 (format 'dd MMMM yyyy 'г.' H:mm:ss')
'    Unable to parse 01 February 2011 г. 07:30:45 (format 'dd MMMM yyyy 'г.' HH:mm:ss')
'    U: Unable to round-trip 4 of 4 format strings.
'    
'    y: All custom format strings round trip.

To parse the string representation of a date and time that can be expressed in a number of predefined custom formats, call one of the following methods:

The custom format strings in the array returned by the GetAllDateTimePatterns method depends on the current calendar of the culture for which the DateTimeFormatInfo object supplies formatting information. If the calendar changes, the array returned by this method also changes.

The following example displays the date and time patterns for the current calendar.

Imports System
Imports System.Globalization
Imports Microsoft.VisualBasic

Public Class SamplesDateTimeFormatInfo    

    Public Shared Sub Main()

        ' Creates a new DateTimeFormatinfo.
        Dim myDtfi As New DateTimeFormatInfo()

        ' Gets and prints all the patterns.
        Dim myPatternsArray As String() = myDtfi.GetAllDateTimePatterns()
        Console.WriteLine("ALL the patterns:")
        PrintIndexAndValues(myPatternsArray)

        ' Gets and prints the pattern(s) associated with some of the format characters.
        myPatternsArray = myDtfi.GetAllDateTimePatterns("d"c)
        Console.WriteLine("The patterns for 'd':")
        PrintIndexAndValues(myPatternsArray)

        myPatternsArray = myDtfi.GetAllDateTimePatterns("D"c)
        Console.WriteLine("The patterns for 'D':")
        PrintIndexAndValues(myPatternsArray)

        myPatternsArray = myDtfi.GetAllDateTimePatterns("f"c)
        Console.WriteLine("The patterns for 'f':")
        PrintIndexAndValues(myPatternsArray)

        myPatternsArray = myDtfi.GetAllDateTimePatterns("F"c)
        Console.WriteLine("The patterns for 'F':")
        PrintIndexAndValues(myPatternsArray)

        myPatternsArray = myDtfi.GetAllDateTimePatterns("r"c)
        Console.WriteLine("The patterns for 'r':")
        PrintIndexAndValues(myPatternsArray)

        myPatternsArray = myDtfi.GetAllDateTimePatterns("R"c)
        Console.WriteLine("The patterns for 'R':")
        PrintIndexAndValues(myPatternsArray)
    End Sub


    Public Shared Sub PrintIndexAndValues(myArray() As String)
        Dim i As Integer = 0
        Dim s As String
        For Each s In  myArray
            Console.WriteLine(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, s)
            i += 1
        Next s
        Console.WriteLine()
    End Sub
End Class


' This code produces the following output.
'
' ALL the patterns:
' 	[0]:	MM/dd/yyyy
' 	[1]:	dddd, dd MMMM yyyy
' 	[2]:	dddd, dd MMMM yyyy HH:mm
' 	[3]:	dddd, dd MMMM yyyy hh:mm tt
' 	[4]:	dddd, dd MMMM yyyy H:mm
' 	[5]:	dddd, dd MMMM yyyy h:mm tt
' 	[6]:	dddd, dd MMMM yyyy HH:mm:ss
' 	[7]:	MM/dd/yyyy HH:mm
' 	[8]:	MM/dd/yyyy hh:mm tt
' 	[9]:	MM/dd/yyyy H:mm
' 	[10]:	MM/dd/yyyy h:mm tt
' 	[11]:	MM/dd/yyyy HH:mm:ss
' 	[12]:	MMMM dd
' 	[13]:	MMMM dd
' 	[14]:	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'
' 	[15]:	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'
' 	[16]:	yyyy'-'MM'-'dd'T'HH':'mm':'ss
' 	[17]:	HH:mm
' 	[18]:	hh:mm tt
' 	[19]:	H:mm
' 	[20]:	h:mm tt
' 	[21]:	HH:mm:ss
' 	[22]:	yyyy'-'MM'-'dd HH':'mm':'ss'Z'
' 	[23]:	dddd, dd MMMM yyyy HH:mm:ss
' 	[24]:	yyyy MMMM
' 	[25]:	yyyy MMMM
' 
' The patterns for 'd':
' 	[0]:	MM/dd/yyyy
' 
' The patterns for 'D':
' 	[0]:	dddd, dd MMMM yyyy
' 
' The patterns for 'f':
' 	[0]:	dddd, dd MMMM yyyy HH:mm
' 	[1]:	dddd, dd MMMM yyyy hh:mm tt
' 	[2]:	dddd, dd MMMM yyyy H:mm
' 	[3]:	dddd, dd MMMM yyyy h:mm tt
' 
' The patterns for 'F':
' 	[0]:	dddd, dd MMMM yyyy HH:mm:ss
' 
' The patterns for 'r':
' 	[0]:	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'
' 
' The patterns for 'R':
' 	[0]:	ddd, dd MMM yyyy HH':'mm':'ss 'GMT'
' 

.NET Framework
Available since 1.1
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