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.NET Framework Class Library
StringInfo Class

Provides functionality to split a string into text elements and to iterate through those text elements.

Inheritance Hierarchy
SystemObject
  System.GlobalizationStringInfo

Namespace:   System.Globalization
Assemblies:   mscorlib (in mscorlib.dll)
  System.Globalization (in System.Globalization.dll)
Syntax
<[%$TOPIC/c4hkht93_en-us_VS_110_2_0_0_0_0%]> _
<[%$TOPIC/c4hkht93_en-us_VS_110_2_0_0_0_1%](True)> _
Public Class StringInfo
[[%$TOPIC/c4hkht93_en-us_VS_110_2_0_1_0_0%]]
[[%$TOPIC/c4hkht93_en-us_VS_110_2_0_1_0_1%](true)]
public class StringInfo
[[%$TOPIC/c4hkht93_en-us_VS_110_2_0_2_0_0%]]
[[%$TOPIC/c4hkht93_en-us_VS_110_2_0_2_0_1%](true)]
public ref class StringInfo
[<[%$TOPIC/c4hkht93_en-us_VS_110_2_0_3_0_0%]>]
[<[%$TOPIC/c4hkht93_en-us_VS_110_2_0_3_0_1%](true)>]
type StringInfo =  class end
public class StringInfo

The StringInfo type exposes the following members.

Constructors
  NameDescription
Public method Supported by the XNA Framework Supported by Portable Class Library StringInfoInitializes a new instance of the StringInfo class.
Public method Supported by the XNA Framework Supported by Portable Class Library StringInfo(String)Initializes a new instance of the StringInfo class to a specified string.
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Properties
  NameDescription
Public property Supported by the XNA Framework Supported by Portable Class Library LengthInTextElementsGets the number of text elements in the current StringInfo object.
Public property Supported by the XNA Framework Supported by Portable Class Library StringGets or sets the value of the current StringInfo object.
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Methods
  NameDescription
Public method Supported by the XNA Framework Supported by Portable Class Library EqualsIndicates whether the current StringInfo object is equal to a specified object. (Overrides ObjectEquals(Object).)
Protected method Supported by the XNA Framework Supported by Portable Class Library FinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method Supported by the XNA Framework Supported by Portable Class Library GetHashCodeCalculates a hash code for the value of the current StringInfo object. (Overrides ObjectGetHashCode.)
Public method Static member Supported by the XNA Framework Supported by Portable Class Library GetNextTextElement(String)Gets the first text element in a specified string.
Public method Static member Supported by the XNA Framework Supported by Portable Class Library GetNextTextElement(String, Int32)Gets the text element at the specified index of the specified string.
Public method Static member Supported by the XNA Framework Supported by Portable Class Library GetTextElementEnumerator(String)Returns an enumerator that iterates through the text elements of the entire string.
Public method Static member Supported by the XNA Framework Supported by Portable Class Library GetTextElementEnumerator(String, Int32)Returns an enumerator that iterates through the text elements of the string, starting at the specified index.
Public method Supported by the XNA Framework Supported by Portable Class Library GetTypeGets the Type of the current instance. (Inherited from Object.)
Protected method Supported by the XNA Framework Supported by Portable Class Library MemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public method Static member Supported by the XNA Framework Supported by Portable Class Library ParseCombiningCharactersReturns the indexes of each base character, high surrogate, or control character within the specified string.
Public method SubstringByTextElements(Int32)Retrieves a substring of text elements from the current StringInfo object starting from a specified text element and continuing through the last text element.
Public method SubstringByTextElements(Int32, Int32)Retrieves a substring of text elements from the current StringInfo object starting from a specified text element and continuing through the specified number of text elements.
Public method Supported by the XNA Framework Supported by Portable Class Library ToStringReturns a string that represents the current object. (Inherited from Object.)
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Remarks

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 StringInfo class enables you to work with a string as a series of textual elements rather than individual Char objects. You can work with the individual text elements in a string in two ways:

The following example illustrates both ways of working with the text elements in a string. It creates two strings:

  • strCombining, which is a string of Arabic characters that includes three text elements with multiple Char objects. The first text element is the base character ARABIC LETTER ALEF (U+-627) followed by ARABIC HAMZA BELOW (U+-655) and ARABIC KASRA (U+0650). The second text element is ARABIC LETTER HEH (U+0647) followed by ARABIC FATHA (U+-64E). The third text element is ARABIC LETTTER BEH (U+0628) followed by ARABIC DAMMATAN (U+064C).

  • strSurrogates, which is a string that includes three surrogate pairs: GREEK ACROPHONIC FIVE TALENTS (U+10148) from the Supplementary Multilingual Plane, U+20026 from the Supplementary Ideographic Plane, and U+F1001 from the private user area. The UTF-16 encoding of each character is a surrogate pair that consists of a high surrogate followed by a low surrogate.

Each string is parsed once by the ParseCombiningCharacters method and then by the GetTextElementEnumerator method. Both methods correctly parse the text elements in the two strings and display the results of the parsing operation.

Imports System.Globalization

Public Module Example
   Public Sub Main()
      ' The Unicode code points specify Arabic base characters and  
      ' combining character sequences. 
      Dim strCombining As String = ChrW(&H627) & ChrW(&h0655) + ChrW(&H650) & 
              ChrW(&H64A) & ChrW(&H647) & ChrW(&H64E) & ChrW(&H627) & 
              ChrW(&H628) & ChrW(&H64C)

      ' The Unicode code points specify private surrogate pairs. 
      Dim strSurrogates As String = Char.ConvertFromUtf32(&h10148) +
                                    Char.ConvertFromUtf32(&h20026) + "a" +
                                    Char.ConvertFromUtf32(&hF1001)

      EnumerateTextElements(strCombining)
      EnumerateTextElements(strSurrogates)
   End Sub 

   Public Sub EnumerateTextElements(str As String)
      ' Get the Enumerator. 
      Dim teEnum As TextElementEnumerator = Nothing       

      ' Parse the string using the ParseCombiningCharacters method.
      Console.WriteLine()
      Console.WriteLine("Parsing with ParseCombiningCharacters:")
      Dim teIndices As Integer() = StringInfo.ParseCombiningCharacters(str)

      For i As Integer = 0 To teIndices.Length - 1
         If i < teIndices.Length - 1 Then
            Console.WriteLine("Text Element {0} ({1}..{2})= {3}", i, 
               TEIndices(i), TEIndices((i + 1)) - 1, 
               ShowHexValues(str.Substring(TEIndices(i), TEIndices((i + 1)) - 
                             teIndices(i))))
         Else
            Console.WriteLine("Text Element {0} ({1}..{2})= {3}", i, 
               teIndices(i), str.Length - 1, 
               ShowHexValues(str.Substring(teIndices(i))))
         End If 
      Next
      Console.WriteLine()

      ' Parse the string with the GetTextElementEnumerator method.
      Console.WriteLine("Parsing with TextElementEnumerator:")
      teEnum = StringInfo.GetTextElementEnumerator(str)

      Dim TECount As Integer = - 1

      While teEnum.MoveNext()
         ' Prints the current element. 
         ' Both GetTextElement() and Current retrieve the current 
         ' text element. The latter returns it as an Object.
         TECount += 1
         Console.WriteLine("Text Element {0} ({1}..{2})= {3}", teCount, 
            teEnum.ElementIndex, teEnum.ElementIndex + 
            teEnum.GetTextElement().Length - 1, ShowHexValues(CStr(teEnum.Current)))
      End While 
   End Sub 

   Private Function ShowHexValues(s As String) As String 
      Dim hexString As String = "" 
      For Each ch In s
         hexString += String.Format("{0:X4} ", Convert.ToUInt16(ch))
      Next 
      Return hexString
   End Function 
End Module 
' The example displays the following output: 
'       Parsing with ParseCombiningCharacters: 
'       Text Element 0 (0..2)= 0627 0655 0650 
'       Text Element 1 (3..3)= 064A 
'       Text Element 2 (4..5)= 0647 064E 
'       Text Element 3 (6..6)= 0627 
'       Text Element 4 (7..8)= 0628 064C 
'        
'       Parsing with TextElementEnumerator: 
'       Text Element 0 (0..2)= 0627 0655 0650 
'       Text Element 1 (3..3)= 064A 
'       Text Element 2 (4..5)= 0647 064E 
'       Text Element 3 (6..6)= 0627 
'       Text Element 4 (7..8)= 0628 064C 
'        
'       Parsing with ParseCombiningCharacters: 
'       Text Element 0 (0..1)= D800 DD48 
'       Text Element 1 (2..3)= D840 DC26 
'       Text Element 2 (4..4)= 0061 
'       Text Element 3 (5..6)= DB84 DC01 
'        
'       Parsing with TextElementEnumerator: 
'       Text Element 0 (0..1)= D800 DD48 
'       Text Element 1 (2..3)= D840 DC26 
'       Text Element 2 (4..4)= 0061 
'       Text Element 3 (5..6)= DB84 DC01
using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      // The Unicode code points specify Arabic base characters and  
      // combining character sequences. 
      string strCombining = "\u0627\u0655\u0650\u064A\u0647\u064E" +
                            "\u0627\u0628\u064C";

      // The Unicode code points specify private surrogate pairs. 
      string strSurrogates = Char.ConvertFromUtf32(0x10148) +
                             Char.ConvertFromUtf32(0x20026) + "a" +
                             Char.ConvertFromUtf32(0xF1001);

      EnumerateTextElements(strCombining);
      EnumerateTextElements(strSurrogates);
   }

   public static void EnumerateTextElements(string str)
   {
      // Get the Enumerator.
      TextElementEnumerator teEnum = null;      

      // Parse the string using the ParseCombiningCharacters method.
      Console.WriteLine("\nParsing with ParseCombiningCharacters:");
      int[] teIndices = StringInfo.ParseCombiningCharacters(str);

      for (int i = 0; i < teIndices.Length; i++) {
         if (i < teIndices.Length - 1)
            Console.WriteLine("Text Element {0} ({1}..{2})= {3}", i, 
               teIndices[i], teIndices[i + 1] - 1, 
               ShowHexValues(str.Substring(teIndices[i], teIndices[i + 1] - 
                             teIndices[i])));
         else
            Console.WriteLine("Text Element {0} ({1}..{2})= {3}", i, 
               teIndices[i], str.Length - 1, 
               ShowHexValues(str.Substring(teIndices[i])));
      }
      Console.WriteLine();

      // Parse the string with the GetTextElementEnumerator method.
      Console.WriteLine("Parsing with TextElementEnumerator:");
      teEnum = StringInfo.GetTextElementEnumerator(str);

      int teCount = - 1;

      while (teEnum.MoveNext()) {
         // Displays the current element. 
         // Both GetTextElement() and Current retrieve the current 
         // text element. The latter returns it as an Object.
         teCount++;
         Console.WriteLine("Text Element {0} ({1}..{2})= {3}", teCount, 
            teEnum.ElementIndex, teEnum.ElementIndex + 
            teEnum.GetTextElement().Length - 1, ShowHexValues((string)(teEnum.Current)));
      }
   }

   private static string ShowHexValues(string s)
   {
      string hexString = "";
      foreach (var ch in s)
         hexString += String.Format("{0:X4} ", Convert.ToUInt16(ch));

      return hexString;
   }
}
// The example displays the following output: 
//       Parsing with ParseCombiningCharacters: 
//       Text Element 0 (0..2)= 0627 0655 0650 
//       Text Element 1 (3..3)= 064A 
//       Text Element 2 (4..5)= 0647 064E 
//       Text Element 3 (6..6)= 0627 
//       Text Element 4 (7..8)= 0628 064C 
//        
//       Parsing with TextElementEnumerator: 
//       Text Element 0 (0..2)= 0627 0655 0650 
//       Text Element 1 (3..3)= 064A 
//       Text Element 2 (4..5)= 0647 064E 
//       Text Element 3 (6..6)= 0627 
//       Text Element 4 (7..8)= 0628 064C 
//        
//       Parsing with ParseCombiningCharacters: 
//       Text Element 0 (0..1)= D800 DD48 
//       Text Element 1 (2..3)= D840 DC26 
//       Text Element 2 (4..4)= 0061 
//       Text Element 3 (5..6)= DB84 DC01 
//        
//       Parsing with TextElementEnumerator: 
//       Text Element 0 (0..1)= D800 DD48 
//       Text Element 1 (2..3)= D840 DC26 
//       Text Element 2 (4..4)= 0061 
//       Text Element 3 (5..6)= DB84 DC01
Examples

This example shows how to use the GetTextElementEnumerator and ParseCombiningCharacters methods of the StringInfo class to manipulate a string that contains surrogate and combining characters.

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
using System;
using System.Text;
using System.Globalization;

public sealed class App {
   static void Main() {
      // The string below contains combining characters.
      String s = "a\u0304\u0308bc\u0327";

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

      // Show the index in the string where each 'character' starts.
      EnumTextElementIndexes(s);
   }

   // Show how to enumerate each real character (honoring surrogates) in a string. 
   static void EnumTextElements(String s) {
      // This StringBuilder holds the output results.
      StringBuilder sb = new StringBuilder();

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

      // Show the results.
      Console.WriteLine("Result of GetTextElementEnumerator:");
      Console.WriteLine(sb);
   }

   // Show how to discover the index of each real character (honoring surrogates) in a string. 
   static void EnumTextElementIndexes(String s) {
      // This StringBuilder holds the output results.
      StringBuilder sb = new StringBuilder();

      // Use the ParseCombiningCharacters method to  
      // get the index of each real character in the string.
      Int32[] textElemIndex = StringInfo.ParseCombiningCharacters(s);

      // Iterate through each real character showing the character and the index where it was found. 
      for (Int32 i = 0; i < textElemIndex.Length; i++) {
         sb.AppendFormat(
            "Character {0} starts at index {1}{2}",
            i, textElemIndex[i], Environment.NewLine);
      }

      // Show the results.
      Console.WriteLine("Result of ParseCombiningCharacters:");
      Console.WriteLine(sb);
   }
}

// This code produces 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
using namespace System;
using namespace System::Text;
using namespace System::Globalization;


// Show how to enumerate each real character (honoring surrogates) 
// in a string. 

void EnumTextElements(String^ combiningChars)
{
    // This StringBuilder holds the output results.
    StringBuilder^ sb = gcnew StringBuilder();

    // Use the enumerator returned from GetTextElementEnumerator 
    // method to examine each real character.
    TextElementEnumerator^ charEnum =
        StringInfo::GetTextElementEnumerator(combiningChars);
    while (charEnum->MoveNext())
    {
        sb->AppendFormat("Character at index {0} is '{1}'{2}", 
            charEnum->ElementIndex, charEnum->GetTextElement(), 
            Environment::NewLine);
    }

    // Show the results.
    Console::WriteLine("Result of GetTextElementEnumerator:");
    Console::WriteLine(sb);
}


// Show how to discover the index of each real character 
// (honoring surrogates) in a string. 

void EnumTextElementIndexes(String^ combiningChars)
{
    // This StringBuilder holds the output results.
    StringBuilder^ sb = gcnew StringBuilder();

    // Use the ParseCombiningCharacters method to 
    // get the index of each real character in the string. 
    array <int>^ textElemIndex =
        StringInfo::ParseCombiningCharacters(combiningChars);

    // Iterate through each real character showing the character 
    // and the index where it was found. 
    for (int i = 0; i < textElemIndex->Length; i++)
    {
        sb->AppendFormat("Character {0} starts at index {1}{2}",
            i, textElemIndex[i], Environment::NewLine);
    }

    // Show the results.
    Console::WriteLine("Result of ParseCombiningCharacters:");
    Console::WriteLine(sb);
}

int main()
{

    // The string below contains combining characters.
    String^ combiningChars = L"a\u0304\u0308bc\u0327";

    // Show each 'character' in the string.
    EnumTextElements(combiningChars);

    // Show the index in the string where each 'character' starts.
    EnumTextElementIndexes(combiningChars);

};

// This code produces 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
Version Information

.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
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.