StringComparer Classe

Definição

public ref class StringComparer abstract : System::Collections::Generic::IComparer<System::String ^>, System::Collections::Generic::IEqualityComparer<System::String ^>, System::Collections::IComparer, System::Collections::IEqualityComparer

public abstract class StringComparer : System.Collections.Generic.IComparer<string>, System.Collections.Generic.IEqualityComparer<string>, System.Collections.IComparer, System.Collections.IEqualityComparer

[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public abstract class StringComparer : System.Collections.Generic.IComparer<string>, System.Collections.Generic.IEqualityComparer<string>, System.Collections.IComparer, System.Collections.IEqualityComparer

type StringComparer = class
    interface IComparer<string>
    interface IEqualityComparer<string>
    interface IComparer
    interface IEqualityComparer

[<System.Runtime.InteropServices.ComVisible(true)>]
[<System.Serializable>]
type StringComparer = class
    interface IComparer
    interface IEqualityComparer
    interface IComparer<string>
    interface IEqualityComparer<string>

Public MustInherit Class StringComparer
Implements IComparer, IComparer(Of String), IEqualityComparer, IEqualityComparer(Of String)

Herança

Object

StringComparer

Atributos

ComVisibleAttribute SerializableAttribute

Implementações

IComparer<String> IEqualityComparer<String> IComparer IEqualityComparer

Exemplos

O exemplo seguinte demonstra as propriedades e o Create método da StringComparer classe. O exemplo ilustra como diferentes StringComparer objetos classificam três versões da letra latina I.

// This example demonstrates members of the 
// System.StringComparer class.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Threading;

class Sample 
{
    public static void Main() 
    {
        // Create a list of string.
        List<string> list = new List<string>();

        // Get the tr-TR (Turkish-Turkey) culture.
        CultureInfo turkish = new CultureInfo("tr-TR");

        // Get the culture that is associated with the current thread.
        CultureInfo thisCulture = Thread.CurrentThread.CurrentCulture;

        // Get the standard StringComparers.
        StringComparer invCmp =   StringComparer.InvariantCulture;
        StringComparer invICCmp = StringComparer.InvariantCultureIgnoreCase;
        StringComparer currCmp = StringComparer.CurrentCulture;
        StringComparer currICCmp = StringComparer.CurrentCultureIgnoreCase;
        StringComparer ordCmp = StringComparer.Ordinal;
        StringComparer ordICCmp = StringComparer.OrdinalIgnoreCase;

        // Create a StringComparer that uses the Turkish culture and ignores case.
        StringComparer turkICComp = StringComparer.Create(turkish, true);

        // Define three strings consisting of different versions of the letter I.
        // LATIN CAPITAL LETTER I (U+0049)
        string capitalLetterI = "I";  

        // LATIN SMALL LETTER I (U+0069)
        string smallLetterI   = "i";

        // LATIN SMALL LETTER DOTLESS I (U+0131)
        string smallLetterDotlessI = "\u0131";

        // Add the three strings to the list.
        list.Add(capitalLetterI);
        list.Add(smallLetterI);
        list.Add(smallLetterDotlessI);

        // Display the original list order.
        Display(list, "The original order of the list entries...");

        // Sort the list using the invariant culture.
        list.Sort(invCmp);
        Display(list, "Invariant culture...");
        list.Sort(invICCmp);
        Display(list, "Invariant culture, ignore case...");

        // Sort the list using the current culture.
        Console.WriteLine("The current culture is \"{0}\".", thisCulture.Name);
        list.Sort(currCmp);
        Display(list, "Current culture...");
        list.Sort(currICCmp);
        Display(list, "Current culture, ignore case...");

        // Sort the list using the ordinal value of the character code points.
        list.Sort(ordCmp);
        Display(list, "Ordinal...");
        list.Sort(ordICCmp);
        Display(list, "Ordinal, ignore case...");

        // Sort the list using the Turkish culture, which treats LATIN SMALL LETTER 
        // DOTLESS I differently than LATIN SMALL LETTER I.
        list.Sort(turkICComp);
        Display(list, "Turkish culture, ignore case...");
    }

    public static void Display(List<string> lst, string title)
    {
        Char c;
        int  codePoint;
        Console.WriteLine(title);
        foreach (string s in lst)
        {
            c = s[0];
            codePoint = Convert.ToInt32(c);
            Console.WriteLine("0x{0:x}", codePoint); 
        }
        Console.WriteLine();
    }
}
/*
This code example produces the following results:

The original order of the list entries...
0x49
0x69
0x131

Invariant culture...
0x69
0x49
0x131

Invariant culture, ignore case...
0x49
0x69
0x131

The current culture is "en-US".
Current culture...
0x69
0x49
0x131

Current culture, ignore case...
0x49
0x69
0x131

Ordinal...
0x49
0x69
0x131

Ordinal, ignore case...
0x69
0x49
0x131

Turkish culture, ignore case...
0x131
0x49
0x69

*/

// This example demonstrates members of the 
// System.StringComparer class.

open System
open System.Globalization
open System.Threading

let display (lst: ResizeArray<string>) title =
    printfn $"%s{title}"
    for s in lst do
        let c = s[0]
        let codePoint = Convert.ToInt32 c
        printfn $"0x{codePoint:x}"
    printfn ""

// Create a list of string.
let list = ResizeArray()

// Get the tr-TR (Turkish-Turkey) culture.
let turkish = CultureInfo "tr-TR"

// Get the culture that is associated with the current thread.
let thisCulture = Thread.CurrentThread.CurrentCulture

// Get the standard StringComparers.
let invCmp =   StringComparer.InvariantCulture
let invICCmp = StringComparer.InvariantCultureIgnoreCase
let currCmp = StringComparer.CurrentCulture
let currICCmp = StringComparer.CurrentCultureIgnoreCase
let ordCmp = StringComparer.Ordinal
let ordICCmp = StringComparer.OrdinalIgnoreCase

// Create a StringComparer that uses the Turkish culture and ignores case.
let turkICComp = StringComparer.Create(turkish, true)

// Define three strings consisting of different versions of the letter I.
// LATIN CAPITAL LETTER I (U+0049)
let capitalLetterI = "I"  

// LATIN SMALL LETTER I (U+0069)
let smallLetterI   = "i"

// LATIN SMALL LETTER DOTLESS I (U+0131)
let smallLetterDotlessI = "\u0131"

// Add the three strings to the list.
list.Add capitalLetterI
list.Add smallLetterI
list.Add smallLetterDotlessI

// Display the original list order.
display list "The original order of the list entries..."

// Sort the list using the invariant culture.
list.Sort invCmp
display list "Invariant culture..."
list.Sort invICCmp
display list "Invariant culture, ignore case..."

// Sort the list using the current culture.
printfn $"The current culture is \"{thisCulture.Name}\"."
list.Sort currCmp
display list "Current culture..."
list.Sort currICCmp
display list "Current culture, ignore case..."

// Sort the list using the ordinal value of the character code points.
list.Sort ordCmp
display list "Ordinal..."
list.Sort ordICCmp
display list "Ordinal, ignore case..."

// Sort the list using the Turkish culture, which treats LATIN SMALL LETTER 
// DOTLESS I differently than LATIN SMALL LETTER I.
list.Sort turkICComp
display list "Turkish culture, ignore case..."


(*
This code example produces the following results:

The original order of the list entries...
0x49
0x69
0x131

Invariant culture...
0x69
0x49
0x131

Invariant culture, ignore case...
0x49
0x69
0x131

The current culture is "en-US".
Current culture...
0x69
0x49
0x131

Current culture, ignore case...
0x49
0x69
0x131

Ordinal...
0x49
0x69
0x131

Ordinal, ignore case...
0x69
0x49
0x131

Turkish culture, ignore case...
0x131
0x49
0x69

*)

' This code example demonstrates members of the System.StringComparer class.

Imports System.Collections
Imports System.Collections.Generic
Imports System.Globalization
Imports System.Threading

Class Sample
    
    Public Shared Sub Main() 
        ' Create a list of string.
        Dim list As New List(Of String) 
        
        ' Get the tr-TR (Turkish-Turkey) culture.
        Dim turkish As New CultureInfo("tr-TR")
        
        ' Get the culture that is associated with the current thread.
        Dim thisCulture As CultureInfo = Thread.CurrentThread.CurrentCulture
        
        ' Get the standard StringComparers.
        Dim invCmp As StringComparer = StringComparer.InvariantCulture
        Dim invICCmp As StringComparer = StringComparer.InvariantCultureIgnoreCase
        Dim currCmp As StringComparer = StringComparer.CurrentCulture
        Dim currICCmp As StringComparer = StringComparer.CurrentCultureIgnoreCase
        Dim ordCmp As StringComparer = StringComparer.Ordinal
        Dim ordICCmp As StringComparer = StringComparer.OrdinalIgnoreCase
        
        ' Create a StringComparer that uses the Turkish culture and ignores case.
        Dim turkICComp As StringComparer = StringComparer.Create(turkish, True)
        
        ' Define three strings consisting of different versions of the letter I.
        ' LATIN CAPITAL LETTER I (U+0049)
        Dim capitalLetterI As String = "I"
        
        ' LATIN SMALL LETTER I (U+0069)
        Dim smallLetterI As String = "i"
        
        ' LATIN SMALL LETTER DOTLESS I (U+0131)
        Dim smallLetterDotlessI As String = "ı"
        
        ' Add the three strings to the list.
        list.Add(capitalLetterI)
        list.Add(smallLetterI)
        list.Add(smallLetterDotlessI)
        
        ' Display the original list order.
        Display(list, "The original order of the list entries...")
        
        ' Sort the list using the invariant culture.
        list.Sort(invCmp)
        Display(list, "Invariant culture...")
        list.Sort(invICCmp)
        Display(list, "Invariant culture, ignore case...")
        
        ' Sort the list using the current culture.
        Console.WriteLine("The current culture is ""{0}"".", thisCulture.Name)
        list.Sort(currCmp)
        Display(list, "Current culture...")
        list.Sort(currICCmp)
        Display(list, "Current culture, ignore case...")
        
        ' Sort the list using the ordinal value of the character code points.
        list.Sort(ordCmp)
        Display(list, "Ordinal...")
        list.Sort(ordICCmp)
        Display(list, "Ordinal, ignore case...")
        
        ' Sort the list using the Turkish culture, which treats LATIN SMALL LETTER 
        ' DOTLESS I differently than LATIN SMALL LETTER I.
        list.Sort(turkICComp)
        Display(list, "Turkish culture, ignore case...")
    
    End Sub
    
    Public Shared Sub Display(ByVal lst As List(Of String), ByVal title As String)
        Dim c As Char
        Dim s As String
        Dim codePoint As Integer

        Console.WriteLine(title)
        For Each s In lst
            c = s(0)
            codePoint = Convert.ToInt32(c)
            Console.WriteLine("0x{0:x}", codePoint)
        Next s
        Console.WriteLine()
    End Sub
End Class

'This code example produces the following results:
'
'The original order of the list entries...
'0x49
'0x69
'0x131
'
'Invariant culture...
'0x69
'0x49
'0x131
'
'Invariant culture, ignore case...
'0x49
'0x69
'0x131
'
'The current culture is "en-US".
'Current culture...
'0x69
'0x49
'0x131
'
'Current culture, ignore case...
'0x49
'0x69
'0x131
'
'Ordinal...
'0x49
'0x69
'0x131
'
'Ordinal, ignore case...
'0x69
'0x49
'0x131
'
'Turkish culture, ignore case...
'0x131
'0x49
'0x69
'

Observações

Um objeto derivado da classe StringComparer incorpora operações de comparação, igualdade e código hash com base em strings que levam em conta as regras de comparação específicas de maiúsculas e minúsculas e as culturais. Você pode usar a StringComparer classe para criar uma comparação específica do tipo para classificar os elementos em uma coleção genérica. Classes como Hashtable, Dictionary<TKey,TValue>, SortedList, e SortedList<TKey,TValue> usam a StringComparer classe para fins de classificação.

Uma operação de comparação representada pela classe StringComparer é definida como sensível ou insensível a maiúsculas/minúsculas, e utiliza regras de comparação por palavras (sensíveis à cultura) ou ordinais (insensíveis à cultura). Para obter mais informações sobre regras de comparação de palavras e ordinais, consulte System.Globalization.CompareOptions.

Propriedades implementadas

Você pode estar confuso sobre como usar as StringComparer propriedades de classe devido a uma aparente contradição. A StringComparer classe é declarada abstract (MustInherit no Visual Basic), o que significa que seus membros podem ser invocados somente em um objeto de uma classe derivada da StringComparer classe. A contradição é que cada propriedade da classe é declarada StringComparerstatic (Shared no Visual Basic), o que significa que a propriedade pode ser invocada sem primeiro criar uma classe derivada.

Você pode chamar uma StringComparer propriedade diretamente porque cada propriedade realmente retorna uma instância de uma classe anônima que é derivada da StringComparer classe. Consequentemente, o tipo de cada valor de propriedade é StringComparer, que é a classe base da classe anônima, não o tipo da classe anônima em si. Cada StringComparer propriedade de classe retorna um StringComparer objeto que oferece suporte a regras predefinidas de comparação e de caixa.

Ver também

• String
• CompareOptions