Comparer Class

Definition

Namespace:

System.Collections

Assembly:

System.Runtime.dll

Source:

Comparer.cs

Compares two objects for equivalence, where string comparisons are case-sensitive.

public ref class Comparer sealed : System::Collections::IComparer, System::Runtime::Serialization::ISerializable

public sealed class Comparer : System.Collections.IComparer, System.Runtime.Serialization.ISerializable

type Comparer = class
    interface IComparer
    interface ISerializable

Public NotInheritable Class Comparer
Implements IComparer, ISerializable

Inheritance

Object

Comparer

Implements

IComparer ISerializable

Examples

The following code example shows how Compare returns different values depending on the culture associated with the Comparer.

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

Remarks

This class is the default implementation of the IComparer interface. The CaseInsensitiveComparer class is the implementation of the IComparer interface that performs case-insensitive string comparisons. System.Collections.Generic.Comparer<T> is the generic equivalent of this class.

Comparison procedures use the Thread.CurrentCulture of the current thread unless otherwise specified. String comparisons might have different results depending on the culture. For more information on culture-specific comparisons, see the System.Globalization namespace and Globalization and Localization.

Constructors

Comparer(CultureInfo)

Initializes a new instance of the Comparer class using the specified CultureInfo.

Fields

Default	Represents an instance of Comparer that is associated with the CurrentCulture of the current thread. This field is read-only.
DefaultInvariant	Represents an instance of Comparer that is associated with InvariantCulture. This field is read-only.

Methods

Compare(Object, Object)	Performs a case-sensitive 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)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetObjectData(SerializationInfo, StreamingContext)	Obsolete. Populates a SerializationInfo object with the data required for serialization.
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• IComparer
• IComparable
• CaseInsensitiveComparer
• Comparer<T>
• CompareInfo
• CurrentCulture
• CultureInfo