CaseInsensitiveComparer 类

定义

比较两个对象是否相等,比较时忽略字符串的大小写。Compares two objects for equivalence, ignoring the case of strings.

public ref class CaseInsensitiveComparer : System::Collections::IComparer
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public class CaseInsensitiveComparer : System.Collections.IComparer
type CaseInsensitiveComparer = class
    interface IComparer
Public Class CaseInsensitiveComparer
Implements IComparer
继承
CaseInsensitiveComparer
属性
实现

示例

下面的代码示例创建区分大小写的哈希表和不区分大小写的哈希表,并演示其行为中的差异,即使两者都包含相同的元素也是如此。The following code example creates a case-sensitive hash table and a case-insensitive hash table and demonstrates the difference in their behavior, even if both contain the same elements.

using namespace System;
using namespace System::Collections;
using namespace System::Globalization;
int main()
{
   
   // Create a Hashtable using the default hash code provider and the default comparer.
   Hashtable^ myHT1 = gcnew Hashtable;
   myHT1->Add( "FIRST", "Hello" );
   myHT1->Add( "SECOND", "World" );
   myHT1->Add( "THIRD", "!" );
   
   // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
   // based on the culture of the current thread.
   Hashtable^ myHT2 = gcnew Hashtable( gcnew CaseInsensitiveHashCodeProvider,gcnew CaseInsensitiveComparer );
   myHT2->Add( "FIRST", "Hello" );
   myHT2->Add( "SECOND", "World" );
   myHT2->Add( "THIRD", "!" );
   
   // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
   // based on the InvariantCulture.
   Hashtable^ myHT3 = gcnew Hashtable( CaseInsensitiveHashCodeProvider::DefaultInvariant,CaseInsensitiveComparer::DefaultInvariant );
   myHT3->Add( "FIRST", "Hello" );
   myHT3->Add( "SECOND", "World" );
   myHT3->Add( "THIRD", "!" );
   
   // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
   // based on the Turkish culture (tr-TR), where "I" is not the uppercase version of "i".
   CultureInfo^ myCul = gcnew CultureInfo( "tr-TR" );
   Hashtable^ myHT4 = gcnew Hashtable( gcnew CaseInsensitiveHashCodeProvider( myCul ),gcnew CaseInsensitiveComparer( myCul ) );
   myHT4->Add( "FIRST", "Hello" );
   myHT4->Add( "SECOND", "World" );
   myHT4->Add( "THIRD", "!" );
   
   // Search for a key in each hashtable.
   Console::WriteLine( "first is in myHT1: {0}", myHT1->ContainsKey( "first" ) );
   Console::WriteLine( "first is in myHT2: {0}", myHT2->ContainsKey( "first" ) );
   Console::WriteLine( "first is in myHT3: {0}", myHT3->ContainsKey( "first" ) );
   Console::WriteLine( "first is in myHT4: {0}", myHT4->ContainsKey( "first" ) );
}

/* 
This code produces the following output.  Results vary depending on the system's culture settings.

first is in myHT1: False
first is in myHT2: True
first is in myHT3: True
first is in myHT4: False

*/
using System;
using System.Collections;
using System.Globalization;

public class SamplesHashtable  {

   public static void Main()  {

      // Create a Hashtable using the default hash code provider and the default comparer.
      Hashtable myHT1 = new Hashtable();
      myHT1.Add("FIRST", "Hello");
      myHT1.Add("SECOND", "World");
      myHT1.Add("THIRD", "!");

      // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
      // based on the culture of the current thread.
      Hashtable myHT2 = new Hashtable( new CaseInsensitiveHashCodeProvider(), new CaseInsensitiveComparer() );
      myHT2.Add("FIRST", "Hello");
      myHT2.Add("SECOND", "World");
      myHT2.Add("THIRD", "!");

      // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
      // based on the InvariantCulture.
      Hashtable myHT3 = new Hashtable( CaseInsensitiveHashCodeProvider.DefaultInvariant, CaseInsensitiveComparer.DefaultInvariant );
      myHT3.Add("FIRST", "Hello");
      myHT3.Add("SECOND", "World");
      myHT3.Add("THIRD", "!");

      // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
      // based on the Turkish culture (tr-TR), where "I" is not the uppercase version of "i".
      CultureInfo myCul = new CultureInfo( "tr-TR" );
      Hashtable myHT4 = new Hashtable( new CaseInsensitiveHashCodeProvider( myCul ), new CaseInsensitiveComparer( myCul ) );
      myHT4.Add("FIRST", "Hello");
      myHT4.Add("SECOND", "World");
      myHT4.Add("THIRD", "!");

      // Search for a key in each hashtable.
      Console.WriteLine( "first is in myHT1: {0}", myHT1.ContainsKey( "first" ) );
      Console.WriteLine( "first is in myHT2: {0}", myHT2.ContainsKey( "first" ) );
      Console.WriteLine( "first is in myHT3: {0}", myHT3.ContainsKey( "first" ) );
      Console.WriteLine( "first is in myHT4: {0}", myHT4.ContainsKey( "first" ) );
   }
}


/* 
This code produces the following output.  Results vary depending on the system's culture settings.

first is in myHT1: False
first is in myHT2: True
first is in myHT3: True
first is in myHT4: False

*/

Imports System.Collections
Imports System.Globalization

Public Class SamplesHashtable

   Public Shared Sub Main()

      ' Create a Hashtable using the default hash code provider and the default comparer.
      Dim myHT1 As New Hashtable()
      myHT1.Add("FIRST", "Hello")
      myHT1.Add("SECOND", "World")
      myHT1.Add("THIRD", "!")

      ' Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
      ' based on the culture of the current thread.
      Dim myHT2 As New Hashtable(New CaseInsensitiveHashCodeProvider(), New CaseInsensitiveComparer())
      myHT2.Add("FIRST", "Hello")
      myHT2.Add("SECOND", "World")
      myHT2.Add("THIRD", "!")

      ' Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
      ' based on the InvariantCulture.
      Dim myHT3 As New Hashtable(CaseInsensitiveHashCodeProvider.DefaultInvariant, CaseInsensitiveComparer.DefaultInvariant)
      myHT3.Add("FIRST", "Hello")
      myHT3.Add("SECOND", "World")
      myHT3.Add("THIRD", "!")

      ' Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer,
      ' based on the Turkish culture (tr-TR), where "I" is not the uppercase version of "i".
      Dim myCul As New CultureInfo("tr-TR")
      Dim myHT4 As New Hashtable(New CaseInsensitiveHashCodeProvider(myCul), New CaseInsensitiveComparer(myCul))
      myHT4.Add("FIRST", "Hello")
      myHT4.Add("SECOND", "World")
      myHT4.Add("THIRD", "!")

      ' Search for a key in each hashtable.
      Console.WriteLine("first is in myHT1: {0}", myHT1.ContainsKey("first"))
      Console.WriteLine("first is in myHT2: {0}", myHT2.ContainsKey("first"))
      Console.WriteLine("first is in myHT3: {0}", myHT3.ContainsKey("first"))
      Console.WriteLine("first is in myHT4: {0}", myHT4.ContainsKey("first"))

   End Sub

End Class


'This code produces the following output.  Results vary depending on the system's culture settings.
'
'first is in myHT1: False
'first is in myHT2: True
'first is in myHT3: True
'first is in myHT4: False

注解

CaseInsensitiveComparer 实现了在字符串上支持不区分大小写的比较的 IComparer 接口,就像 CaseInsensitiveHashCodeProvider 实现支持对字符串进行不区分大小写的比较的 IHashCodeProvider 接口。CaseInsensitiveComparer implements the IComparer interface supporting case-insensitive comparisons on strings, just as CaseInsensitiveHashCodeProvider implements the IHashCodeProvider interface supporting case-insensitive comparisons on strings.

重要

建议不要将 CaseInsensitiveComparer 类用于新的开发。We don't recommend that you use the CaseInsensitiveComparer class for new development. 相反,我们建议使用 StringComparer.CurrentCultureIgnoreCaseStringComparer.InvariantCultureIgnoreCaseStringComparer.OrdinalIgnoreCase 属性返回的 System.StringComparer 对象。Instead, we recommend that you use the System.StringComparer object returned by the StringComparer.CurrentCultureIgnoreCase, StringComparer.InvariantCultureIgnoreCase, or StringComparer.OrdinalIgnoreCase property.

Comparer 类是 IComparer 接口的默认实现,并执行区分大小写的字符串比较。The Comparer class is the default implementation of the IComparer interface and performs case-sensitive string comparisons.

Hashtable 需要重写 Object.GetHashCode 方法(或 IHashCodeProvider 接口)和 Object.Equals 方法(或 IComparer 接口)作为键使用的对象。The objects used as keys by a Hashtable are required to override the Object.GetHashCode method (or the IHashCodeProvider interface) and the Object.Equals method (or the IComparer interface). 方法或接口的实现必须以相同的方式处理区分大小写。否则,Hashtable 的行为可能不正确。The implementation of both methods or interfaces must handle case sensitivity the same way; otherwise, the Hashtable might behave incorrectly. 例如,在创建 Hashtable时,必须将此类与 CaseInsensitiveHashCodeProvider 类或任何不区分大小写的 IHashCodeProvider 实现一起使用。For example, when creating a Hashtable, you must use this class with the CaseInsensitiveHashCodeProvider class or any case-insensitive IHashCodeProvider implementation.

根据区域性,字符串比较可能会产生不同的结果。String comparisons might have different results depending on the culture. 有关区域性特定比较的详细信息,请参阅 System.Globalization 命名空间以及全球化和本地化For more information on culture-specific comparisons, see the System.Globalization namespace and Globalization and Localization.

构造函数

CaseInsensitiveComparer()

使用当前线程的 CaseInsensitiveComparer 初始化 CurrentCulture 类的新实例。Initializes a new instance of the CaseInsensitiveComparer class using the CurrentCulture of the current thread.

CaseInsensitiveComparer(CultureInfo)

使用指定的 CaseInsensitiveComparer 初始化 CultureInfo 类的新实例。Initializes a new instance of the CaseInsensitiveComparer class using the specified CultureInfo.

属性

Default

获取 CaseInsensitiveComparer 的一个实例,该实例与当前线程的 CurrentCulture 关联并且始终可用。Gets an instance of CaseInsensitiveComparer that is associated with the CurrentCulture of the current thread and that is always available.

DefaultInvariant

获取 CaseInsensitiveComparer 的一个实例,该实例与 InvariantCulture 关联并且始终可用。Gets an instance of CaseInsensitiveComparer that is associated with InvariantCulture and that is always available.

方法

Compare(Object, Object)

对同一类型的两个对象执行不区分大小写的比较,并返回一个值,指示其中一个对象是小于、等于还是大于另一个对象。Performs a case-insensitive comparison of two objects of the same type and returns a value indicating whether one is less than, equal to, or greater than the other.

Equals(Object)

确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(继承自 Object)
GetHashCode()

用作默认哈希函数。Serves as the default hash function.

(继承自 Object)
GetType()

获取当前实例的 TypeGets the Type of the current instance.

(继承自 Object)
MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(继承自 Object)
ToString()

返回一个表示当前对象的 string。Returns a string that represents the current object.

(继承自 Object)

适用于

另请参阅