CompareInfo.Compare Method (String, String, CompareOptions)


Compares two strings using the specified CompareOptions value.

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

public virtual int Compare(
	string string1,
	string string2,
	CompareOptions options


Type: System.String

The first string to compare.

Type: System.String

The second string to compare.

Type: System.Globalization.CompareOptions

A value that defines how string1 and string2 should be compared. options is either the enumeration value Ordinal, or a bitwise combination of one or more of the following values: IgnoreCase, IgnoreSymbols, IgnoreNonSpace, IgnoreWidth, IgnoreKanaType, and StringSort.

Return Value

Type: System.Int32

A 32-bit signed integer indicating the lexical relationship between the two comparands.




The two strings are equal.

less than zero

string1 is less than string2.

greater than zero

string1 is greater than string2.

Exception Condition

options contains an invalid CompareOptions value.

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.


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, CompareOptions) method does not consider such characters when it performs a culture-sensitive comparison. To recognize ignorable characters in your comparison, supply a value of CompareOptions.Ordinal or CompareOptions.OrdinalIgnoreCase for the options parameter.

The following example compares two strings using different CompareOptions settings.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Defines the strings to compare.
      String myStr1 = "My Uncle Bill's clients";
      String myStr2 = "My uncle bills clients";

      // Creates a CompareInfo that uses the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Compares two strings using myComp.
      Console.WriteLine( "Comparing \"{0}\" and \"{1}\"", myStr1, myStr2 );
      Console.WriteLine( "   With no CompareOptions            : {0}", myComp.Compare( myStr1, myStr2 ) );
      Console.WriteLine( "   With None                         : {0}", myComp.Compare( myStr1, myStr2, CompareOptions.None ) );
      Console.WriteLine( "   With Ordinal                      : {0}", myComp.Compare( myStr1, myStr2, CompareOptions.Ordinal ) );
      Console.WriteLine( "   With StringSort                   : {0}", myComp.Compare( myStr1, myStr2, CompareOptions.StringSort ) );
      Console.WriteLine( "   With IgnoreCase                   : {0}", myComp.Compare( myStr1, myStr2, CompareOptions.IgnoreCase ) );
      Console.WriteLine( "   With IgnoreSymbols                : {0}", myComp.Compare( myStr1, myStr2, CompareOptions.IgnoreSymbols ) );
      Console.WriteLine( "   With IgnoreCase and IgnoreSymbols : {0}", myComp.Compare( myStr1, myStr2, CompareOptions.IgnoreCase | CompareOptions.IgnoreSymbols ) );



This code produces the following output.

Comparing "My Uncle Bill's clients" and "My uncle bills clients"
   With no CompareOptions            : 1
   With None                         : 1
   With Ordinal                      : -32
   With StringSort                   : -1
   With IgnoreCase                   : 1
   With IgnoreSymbols                : 1
   With IgnoreCase and IgnoreSymbols : 0


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

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top