CompareInfo.Compare Method (String, String)

 
System_CAPS_noteNote

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Compares two strings.

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

Public Overridable Function Compare (
	string1 As String,
	string2 As String
) As Integer

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.

System_CAPS_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.

Imports System
Imports System.Globalization

Public Class SamplesCompareInfo

   Public Shared Sub Main()

      ' Defines the strings to compare.
      Dim myStr1 As [String] = "calle"
      Dim myStr2 As [String] = "calor"

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

      ' Uses GetCompareInfo to create the CompareInfo that uses the "es-ES" culture with traditional sort.
      Dim myCompTrad As CompareInfo = CompareInfo.GetCompareInfo(&H40A)

      ' Uses the CompareInfo property of the InvariantCulture.
      Dim myCompInva As CompareInfo = 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))

   End Sub 'Main 

End Class 'SamplesCompareInfo


'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.

Imports System
Imports System.Text
Imports System.Globalization

NotInheritable Public Class App
    Shared Sub Main(ByVal args() As String) 
        Dim sign() As String = {"<", "=", ">"}

        ' The code below demonstrates how strings compare 
        ' differently for different cultures.
        Dim s1 As String = "Coté"
        Dim s2 As String = "coté"
        Dim s3 As String = "côte"

        ' Set sort order of strings for French in France.
        Dim ci As CompareInfo = 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)))
    End Sub 'Main
End Class 'App

' 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
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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