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CompareInfo.Compare Method (String, String)

Compares two strings.

Namespace:  System.Globalization
Assemblies:   mscorlib (in mscorlib.dll)
  System.Globalization (in System.Globalization.dll)

public virtual int Compare(
	string string1,
	string string2
)

Parameters

string1
Type: System.String

The first string to compare.

string2
Type: System.String

The second string to compare.

Return Value

Type: System.Int32
A 32-bit signed integer indicating the lexical relationship between the two comparands.

Value

Condition

zero

The two strings are equal.

less than zero

string1 is less than string2.

greater than zero

string1 is greater than string2.

By default, the comparison is performed by using CompareOptions.None. If a security decision depends on a string comparison or a case change, you should use the InvariantCulture property to ensure that the behavior is consistent regardless of the culture settings of the operating system.

NoteNote

When possible, you should call string comparison methods that have a parameter of type CompareOptions to specify the kind of comparison expected. As a general rule, use linguistic options (using the current culture) for comparing strings displayed in the user interface and specify Ordinal or OrdinalIgnoreCase for security comparisons.

Notes to Callers

Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. The Compare(String, String) method does not consider such characters when it performs a culture-sensitive comparison. For instance, a culture-sensitive comparison of "animal" with "ani-mal" (using a soft hyphen, or U+00AD) indicates that the two strings are equivalent, as the following example shows.

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim ci As CompareInfo = CultureInfo.CurrentCulture.CompareInfo
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal" 
      Dim s2 As String = "animal"

      Console.WriteLine("Comparison of '{0}' and '{1}': {2}", 
                        s1, s2, ci.Compare(s1, s2))
  End Sub 
End Module 
' The example displays the following output: 
'       Comparison of 'ani-mal' and 'animal': 0

To recognize ignorable characters in a string comparison, call the Compare(String, String, CompareOptions) method and supply a value of either CompareOptions.Ordinal or CompareOptions.OrdinalIgnoreCase for the options parameter.

The following example compares portions of two strings using the different CompareInfo objects:

// The following code example compares two strings using the different CompareInfo instances: 
//    a CompareInfo instance associated with the "Spanish - Spain" culture with international sort,
//    a CompareInfo instance associated with the "Spanish - Spain" culture with traditional sort, and
//    a CompareInfo instance associated with the InvariantCulture. 

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Defines the strings to compare.
      String myStr1 = "calle";
      String myStr2 = "calor";

      // Uses GetCompareInfo to create the CompareInfo that uses the "es-ES" culture with international sort.
      CompareInfo myCompIntl = CompareInfo.GetCompareInfo( "es-ES" );

      // Uses GetCompareInfo to create the CompareInfo that uses the "es-ES" culture with traditional sort.
      CompareInfo myCompTrad = CompareInfo.GetCompareInfo( 0x040A );

      // Uses the CompareInfo property of the InvariantCulture.
      CompareInfo myCompInva = CultureInfo.InvariantCulture.CompareInfo;

      // Compares two strings using myCompIntl.
      Console.WriteLine( "Comparing \"{0}\" and \"{1}\"", myStr1, myStr2 );
      Console.WriteLine( "   With myCompIntl.Compare: {0}", myCompIntl.Compare( myStr1, myStr2 ) );
      Console.WriteLine( "   With myCompTrad.Compare: {0}", myCompTrad.Compare( myStr1, myStr2 ) );
      Console.WriteLine( "   With myCompInva.Compare: {0}", myCompInva.Compare( myStr1, myStr2 ) );

   }

}


/*
This code produces the following output.

Comparing "calle" and "calor"
   With myCompIntl.Compare: -1
   With myCompTrad.Compare: 1
   With myCompInva.Compare: -1

*/

The following example demonstrates calling the Compare method.

using System;
using System.Text;
using System.Globalization;

public sealed class App
{
    static void Main(string[] args)
    {
        String[] sign = new String[] { "<", "=", ">" };

        // The code below demonstrates how strings compare  
        // differently for different cultures.
        String s1 = "Coté", s2 = "coté", s3 = "côte";

        // Set sort order of strings for French in France.
        CompareInfo ci = new CultureInfo("fr-FR").CompareInfo;
        Console.WriteLine("The LCID for {0} is {1}.", ci.Name, ci.LCID);

        // Display the result using fr-FR Compare of Coté = coté.  	
        Console.WriteLine("fr-FR Compare: {0} {2} {1}",
            s1, s2, sign[ci.Compare(s1, s2, CompareOptions.IgnoreCase) + 1]);

        // Display the result using fr-FR Compare of coté > côte.
        Console.WriteLine("fr-FR Compare: {0} {2} {1}",
            s2, s3, sign[ci.Compare(s2, s3, CompareOptions.None) + 1]);

        // Set sort order of strings for Japanese as spoken in Japan.
        ci = new CultureInfo("ja-JP").CompareInfo;
        Console.WriteLine("The LCID for {0} is {1}.", ci.Name, ci.LCID);

        // Display the result using ja-JP Compare of coté < côte. 
        Console.WriteLine("ja-JP Compare: {0} {2} {1}",
            s2, s3, sign[ci.Compare(s2, s3) + 1]);
    }
}

// This code produces the following output. 
//  
// The LCID for fr-FR is 1036. 
// fr-FR Compare: Coté = coté 
// fr-FR Compare: coté > côte 
// The LCID for ja-JP is 1041. 
// ja-JP Compare: coté < côte

.NET Framework

Supported in: 4.6, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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