StringInfo.GetTextElementEnumerator Method (String)

Returns an enumerator that iterates through the text elements of the entire string.

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

'Declaration
Public Shared Function GetTextElementEnumerator ( _
	str As String _
) As TextElementEnumerator

Parameters

str
Type: System.String

The string to iterate through.

Return Value

Type: System.Globalization.TextElementEnumerator
A TextElementEnumerator for the entire string.

ExceptionCondition
ArgumentNullException

str is Nothing.

The .NET Framework defines a text element as a unit of text that is displayed as a single character, that is, a grapheme. A text element can be a base character, a surrogate pair, or a combining character sequence. The Unicode Standard defines a surrogate pair as a coded character representation for a single abstract character that consists of a sequence of two code units, where the first unit of the pair is a high surrogate and the second is a low surrogate. The Unicode Standard defines a combining character sequence as a combination of a base character and one or more combining characters. A surrogate pair can represent a base character or a combining character.

The text element enumerator is used only to read data in the string; it cannot modify the underlying string. The enumerator does not have exclusive access to the string.

The enumerator is in an invalid state if it is positioned before the first text element in the string or after the last text element in the string. When the enumerator is in an invalid state, calling Current throws an exception.

Initially, the enumerator is positioned before the first text element in the string. Reset also brings the enumerator back to this position. Therefore, after an enumerator is created or after Reset is called, MoveNext must be called to advance the enumerator to the first text element of the string before reading the value of Current.

Current returns the same object until either MoveNext or Reset is called.

After the end of the string is passed, the enumerator is again in an invalid state and calling MoveNext returns false. Calling Current throws an exception if the last call to MoveNext returned false.

The following code example demonstrates calling the GetTextElementEnumerator method. This code example is part of a larger example provided for the StringInfo class.

Imports System.Text
Imports System.Globalization

Public Module Example
   Public Sub Main()
      ' The string below contains combining characters. 
      Dim s As String = "a" + ChrW(&h0304) + ChrW(&h0308) + "bc" + ChrW(&h0327)

      ' Show each 'character' in the string.
      EnumTextElements(s)

      ' Show the index in the string where each 'character' starts.
      EnumTextElementIndexes(s)
   End Sub 

   ' Show how to enumerate each real character (honoring surrogates) in a string. 
   Sub EnumTextElements(s As String)
      ' This StringBuilder holds the output results. 
      Dim sb As New StringBuilder()

      ' Use the enumerator returned from GetTextElementEnumerator  
      ' method to examine each real character. 
      Dim charEnum As TextElementEnumerator = StringInfo.GetTextElementEnumerator(s)
      Do While charEnum.MoveNext()
         sb.AppendFormat("Character at index {0} is '{1}'{2}",
                         charEnum.ElementIndex, 
                         charEnum.GetTextElement(),
                         Environment.NewLine)
      Loop 

      ' Show the results.
      Console.WriteLine("Result of GetTextElementEnumerator:")
      Console.WriteLine(sb)
   End Sub 

   ' Show how to discover the index of each real character (honoring surrogates) in a string. 
   Sub EnumTextElementIndexes(s As String)
      ' This StringBuilder holds the output results. 
      Dim sb As New StringBuilder()

      ' Use the ParseCombiningCharacters method to  
      ' get the index of each real character in the string. 
      Dim textElemIndex() As Integer = StringInfo.ParseCombiningCharacters(s)

      ' Iterate through each real character showing the character and the index where it was found. 
      For i As Int32 = 0 To textElemIndex.Length - 1
         sb.AppendFormat("Character {0} starts at index {1}{2}",
                         i, textElemIndex(i), Environment.NewLine)
      Next 

      ' Show the results.
      Console.WriteLine("Result of ParseCombiningCharacters:")
      Console.WriteLine(sb)
   End Sub 
End Module 
' The example displays the following output: 
'       Result of GetTextElementEnumerator: 
'       Character at index 0 is 'a-"' 
'       Character at index 3 is 'b' 
'       Character at index 4 is 'c,' 
'        
'       Result of ParseCombiningCharacters: 
'       Character 0 starts at index 0 
'       Character 1 starts at index 3 
'       Character 2 starts at index 4

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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