Comparer.Compare(Object, Object) 方法

定义

命名空间:

System.Collections

程序集:

System.Runtime.dll

Source:

Comparer.cs

对同一类型的两个对象执行区分大小写的比较，并返回一个值，指示其中一个对象小于、等于还是大于另一个对象。

public:
 virtual int Compare(System::Object ^ a, System::Object ^ b);

public int Compare (object? a, object? b);

abstract member Compare : obj * obj -> int
override this.Compare : obj * obj -> int

Public Function Compare (a As Object, b As Object) As Integer

参数

a

Object

要比较的第一个对象。

b

Object

要比较的第二个对象。

返回

Int32

一个有符号整数，指示 a 和 b 的相对值，如下表所示。

值	含义
小于零	a 小于 b。
零	a 等于 b。
大于零	a 大于 b。

实现

Compare(Object, Object)

例外

ArgumentException

a 和 b 都不实现 IComparable 接口。

- 或 -

a 和 b 的类型不同，它们都无法处理与另一个进行的比较。

示例

下面的代码示例演示如何 Compare 根据与 Comparer关联的区域性返回不同的值。

using namespace System;
using namespace System::Collections;
using namespace System::Globalization;
int main()
{
   
   // Creates the strings to compare.
   String^ str1 = "llegar";
   String^ str2 = "lugar";
   Console::WriteLine( "Comparing \"{0}\" and \"{1}\" ...", str1, str2 );
   
   // Uses the DefaultInvariant Comparer.
   Console::WriteLine( "   Invariant Comparer: {0}", Comparer::DefaultInvariant->Compare( str1, str2 ) );
   
   // Uses the Comparer based on the culture "es-ES" (Spanish - Spain, international sort).
   Comparer^ myCompIntl = gcnew Comparer( gcnew CultureInfo(  "es-ES",false ) );
   Console::WriteLine( "   International Sort: {0}", myCompIntl->Compare( str1, str2 ) );
   
   // Uses the Comparer based on the culture identifier 0x040A (Spanish - Spain, traditional sort).
   Comparer^ myCompTrad = gcnew Comparer( gcnew CultureInfo( 0x040A,false ) );
   Console::WriteLine( "   Traditional Sort  : {0}", myCompTrad->Compare( str1, str2 ) );
}

/*
This code produces the following output.

Comparing "llegar" and "lugar" ...
   Invariant Comparer: -1
   International Sort: -1
   Traditional Sort  : 1

*/

using System;
using System.Collections;
using System.Globalization;

public class SamplesComparer  {

   public static void Main()  {

      // Creates the strings to compare.
      String str1 = "llegar";
      String str2 = "lugar";
      Console.WriteLine( "Comparing \"{0}\" and \"{1}\" ...", str1, str2 );

      // Uses the DefaultInvariant Comparer.
      Console.WriteLine( "   Invariant Comparer: {0}", Comparer.DefaultInvariant.Compare( str1, str2 ) );

      // Uses the Comparer based on the culture "es-ES" (Spanish - Spain, international sort).
      Comparer myCompIntl = new Comparer( new CultureInfo( "es-ES", false ) );
      Console.WriteLine( "   International Sort: {0}", myCompIntl.Compare( str1, str2 ) );

      // Uses the Comparer based on the culture identifier 0x040A (Spanish - Spain, traditional sort).
      Comparer myCompTrad = new Comparer( new CultureInfo( 0x040A, false ) );
      Console.WriteLine( "   Traditional Sort  : {0}", myCompTrad.Compare( str1, str2 ) );
   }
}

/*
This code produces the following output.

Comparing "llegar" and "lugar" ...
   Invariant Comparer: -1
   International Sort: -1
   Traditional Sort  : 1

*/

Imports System.Collections
Imports System.Globalization

Public Class SamplesComparer

   Public Shared Sub Main()

      ' Creates the strings to compare.
      Dim str1 As [String] = "llegar"
      Dim str2 As [String] = "lugar"
      Console.WriteLine("Comparing ""{0}"" and ""{1}"" ...", str1, str2)

      ' Uses the DefaultInvariant Comparer.
      Console.WriteLine("   Invariant Comparer: {0}", Comparer.DefaultInvariant.Compare(str1, str2))

      ' Uses the Comparer based on the culture "es-ES" (Spanish - Spain, international sort).
      Dim myCompIntl As New Comparer(New CultureInfo("es-ES", False))
      Console.WriteLine("   International Sort: {0}", myCompIntl.Compare(str1, str2))

      ' Uses the Comparer based on the culture identifier 0x040A (Spanish - Spain, traditional sort).
      Dim myCompTrad As New Comparer(New CultureInfo(&H40A, False))
      Console.WriteLine("   Traditional Sort  : {0}", myCompTrad.Compare(str1, str2))

   End Sub

End Class


'This code produces the following output.
'
'Comparing "llegar" and "lugar" ...
'   Invariant Comparer: -1
'   International Sort: -1
'   Traditional Sort  : 1

注解

如果 a 实现 IComparable，则为 a。 CompareTob (返回) ;否则，如果 b 实现 IComparable，则返回 的b否定结果。 CompareToa 返回 () 。

null允许与任何类型进行比较，并且在使用 IComparable时不会生成异常。 排序时， null 被视为小于任何其他对象。

字符串比较可能具有不同的结果，具体取决于区域性。 有关特定于区域性的比较的详细信息，请参阅 System.Globalization 命名空间和 全球化和本地化。

另请参阅

• IComparable
• CompareInfo
• CurrentCulture
• CultureInfo