StringInfo.GetTextElementEnumerator 方法

定義

命名空間:

System.Globalization

組件:

System.Runtime.dll

傳回可以逐一查看字串文字項目的列舉值。

多載

GetTextElementEnumerator(String)	傳回可以逐一查看整個字串文字項目的列舉值。
GetTextElementEnumerator(String, Int32)	傳回可以從指定索引處開始來逐一查看字串文字項目的列舉值。

GetTextElementEnumerator(String)

來源:

StringInfo.cs

傳回可以逐一查看整個字串文字項目的列舉值。

public:
 static System::Globalization::TextElementEnumerator ^ GetTextElementEnumerator(System::String ^ str);

public static System.Globalization.TextElementEnumerator GetTextElementEnumerator (string str);

static member GetTextElementEnumerator : string -> System.Globalization.TextElementEnumerator

Public Shared Function GetTextElementEnumerator (str As String) As TextElementEnumerator

參數

str

String

要逐一查看的字串。

傳回

TextElementEnumerator

整個字串的 TextElementEnumerator。

例外狀況

ArgumentNullException

str 為 null。

範例

下列程式碼範例示範如何呼叫 GetTextElementEnumerator 方法。 這個範例是提供給 類別之較大範例的 StringInfo 一部分。

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

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 'ā̈'
// Character at index 3 is 'b'
// Character at index 4 is 'ç'
//
// Result of ParseCombiningCharacters:
// Character 0 starts at index 0
// Character 1 starts at index 3
// Character 2 starts at index 4

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 'ā̈'
'       Character at index 3 is 'b'
'       Character at index 4 is 'ç'
'       
'       Result of ParseCombiningCharacters:
'       Character 0 starts at index 0
'       Character 1 starts at index 3
'       Character 2 starts at index 4

備註

.NET 會將文字元素定義為顯示為單一字元的文字單位，也就是 grapheme。 文字專案可以是基底字元、Surrogate 字組或合併字元序列。 Unicode 標準會將 Surrogate 字組定義為單一抽象字元的自動程式碼字元標記法，其中包含兩個字碼單位的序列，其中配對的第一個單位是高 Surrogate，而第二個則是低 Surrogate。 Unicode 標準會將結合字元序列定義為基底字元和一或多個結合字元的組合。 Surrogate 字組可以代表基底字元或結合字元。

text 元素列舉值只會用來讀取字串中的資料;它無法修改基礎字串。 列舉值沒有字串的獨佔存取權。

如果列舉值位於字串中的第一個文字元素之前或字串中最後一個文字元素之後，列舉值就會處於無效狀態。 當列舉值處於無效狀態時，呼叫 Current 會擲回例外狀況。

一開始，列舉值會放在字串中的第一個文字元素之前。 Reset 也會將列舉值帶回至這個位置。 因此，在建立列舉值或呼叫 之後 Reset ， MoveNext 必須先呼叫 ，才能將列舉值前移至字串的第一個文字元素，然後再讀取 的值 Current 。

Current 會傳回相同的物件直到呼叫 MoveNext 或 Reset。

傳遞字串結尾之後，列舉值會再次處於無效狀態，而呼叫 MoveNext 會傳 false 回 。 如果最後一次呼叫傳 MoveNext 回 ，則呼叫 Current 會擲回例外狀況 false 。

另請參閱

• TextElementEnumerator

GetTextElementEnumerator(String, Int32)

來源:

StringInfo.cs

傳回可以從指定索引處開始來逐一查看字串文字項目的列舉值。

public:
 static System::Globalization::TextElementEnumerator ^ GetTextElementEnumerator(System::String ^ str, int index);

public static System.Globalization.TextElementEnumerator GetTextElementEnumerator (string str, int index);

static member GetTextElementEnumerator : string * int -> System.Globalization.TextElementEnumerator

Public Shared Function GetTextElementEnumerator (str As String, index As Integer) As TextElementEnumerator

參數

str

String

要逐一查看的字串。

index

Int32

要從該處開始反覆查看之以零起始的索引。

傳回

TextElementEnumerator

起始於 index 之字串的 TextElementEnumerator。

例外狀況

ArgumentNullException

str 為 null。

ArgumentOutOfRangeException

index 超出 str 的有效索引範圍。

備註

.NET 會將文字元素定義為顯示為單一字元的文字單位，也就是 grapheme。 文字專案可以是基底字元、Surrogate 字組或合併字元序列。 Unicode 標準會將 Surrogate 字組定義為單一抽象字元的自動程式碼字元標記法，其中包含兩個字碼單位的序列，其中配對的第一個單位是高 Surrogate，而第二個則是低 Surrogate。 Unicode 標準會將結合字元序列定義為基底字元和一或多個結合字元的組合。 Surrogate 字組可以代表基底字元或結合字元。

text 元素列舉值只會用來讀取字串中的資料;它無法修改基礎字串。 列舉值沒有字串的獨佔存取權。

如果列舉值位於字串中的第一個文字元素之前或字串中最後一個文字元素之後，列舉值就會處於無效狀態。 當列舉值處於無效狀態時，呼叫 Current 會擲回例外狀況。

一開始，列舉值會放在字串中的第一個文字元素之前。 Reset 也會將列舉值帶回至這個位置。 因此，在建立列舉值或呼叫 之後 Reset ， MoveNext 必須先呼叫 ，才能將列舉值前移至字串的第一個文字元素，然後再讀取 的值 Current 。

Current 會傳回相同的物件直到呼叫 MoveNext 或 Reset。

傳遞字串結尾之後，列舉值會再次處於無效狀態，而呼叫 MoveNext 會傳 false 回 。 如果最後一次呼叫傳 MoveNext 回 ，則呼叫 Current 會擲回例外狀況 false 。

另請參閱

• TextElementEnumerator