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CompareInfo Class
 

Implements a set of methods for culture-sensitive string comparisons.

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

SystemObject
  System.GlobalizationCompareInfo

[SerializableAttribute]
[ComVisibleAttribute(true)]
public class CompareInfo : IDeserializationCallback
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class CompareInfo : IDeserializationCallback
[<SerializableAttribute>]
[<ComVisibleAttribute(true)>]
type CompareInfo = 
    class
        interface IDeserializationCallback
    end
<SerializableAttribute>
<ComVisibleAttribute(True)>
Public Class CompareInfo
	Implements IDeserializationCallback
NameDescription
System_CAPS_pubproperty

Gets the properly formed culture identifier for the current CompareInfo.

System_CAPS_pubproperty

Gets the name of the culture used for sorting operations by this CompareInfo object.

System_CAPS_pubproperty

Gets information about the version of Unicode used for comparing and sorting strings.

NameDescription
System_CAPS_pubmethod Compare

Compares a section of one string with a section of another string.

System_CAPS_pubmethod Compare

Compares a section of one string with a section of another string using the specified CompareOptions value.

System_CAPS_pubmethod Compare

Compares the end section of a string with the end section of another string.

System_CAPS_pubmethod Compare

Compares the end section of a string with the end section of another string using the specified CompareOptions value.

System_CAPS_pubmethod Compare

Compares two strings.

System_CAPS_pubmethod Compare

Compares two strings using the specified CompareOptions value.

System_CAPS_pubmethod Equals

Determines whether the specified object is equal to the current CompareInfo object.(Overrides ObjectEquals.)

System_CAPS_protmethod Finalize

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethod System_CAPS_static GetCompareInfo

Initializes a new CompareInfo object that is associated with the culture with the specified identifier.

System_CAPS_pubmethod System_CAPS_static GetCompareInfo

Initializes a new CompareInfo object that is associated with the specified culture and that uses string comparison methods in the specified Assembly.

System_CAPS_pubmethod System_CAPS_static GetCompareInfo

Initializes a new CompareInfo object that is associated with the culture with the specified name.

System_CAPS_pubmethod System_CAPS_static GetCompareInfo

Initializes a new CompareInfo object that is associated with the specified culture and that uses string comparison methods in the specified Assembly.

System_CAPS_pubmethod GetHashCode

Serves as a hash function for the current CompareInfo for hashing algorithms and data structures, such as a hash table.(Overrides ObjectGetHashCode.)

System_CAPS_pubmethod GetHashCode

Gets the hash code for a string based on specified comparison options.

System_CAPS_pubmethod GetSortKey

Gets the sort key for the specified string.

System_CAPS_pubmethod GetSortKey

Gets a SortKey object for the specified string using the specified CompareOptions value.

System_CAPS_pubmethod GetType

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethod IndexOf

Searches for the specified character and returns the zero-based index of the first occurrence within the entire source string.

System_CAPS_pubmethod IndexOf

Searches for the specified character and returns the zero-based index of the first occurrence within the entire source string using the specified CompareOptions value.

System_CAPS_pubmethod IndexOf

Searches for the specified character and returns the zero-based index of the first occurrence within the section of the source string that extends from the specified index to the end of the string.

System_CAPS_pubmethod IndexOf

Searches for the specified character and returns the zero-based index of the first occurrence within the section of the source string that extends from the specified index to the end of the string using the specified CompareOptions value.

System_CAPS_pubmethod IndexOf

Searches for the specified character and returns the zero-based index of the first occurrence within the section of the source string that starts at the specified index and contains the specified number of elements.

System_CAPS_pubmethod IndexOf

Searches for the specified character and returns the zero-based index of the first occurrence within the section of the source string that starts at the specified index and contains the specified number of elements using the specified CompareOptions value.

System_CAPS_pubmethod IndexOf

Searches for the specified substring and returns the zero-based index of the first occurrence within the entire source string.

System_CAPS_pubmethod IndexOf

Searches for the specified substring and returns the zero-based index of the first occurrence within the entire source string using the specified CompareOptions value.

System_CAPS_pubmethod IndexOf

Searches for the specified substring and returns the zero-based index of the first occurrence within the section of the source string that extends from the specified index to the end of the string.

System_CAPS_pubmethod IndexOf

Searches for the specified substring and returns the zero-based index of the first occurrence within the section of the source string that extends from the specified index to the end of the string using the specified CompareOptions value.

System_CAPS_pubmethod IndexOf

Searches for the specified substring and returns the zero-based index of the first occurrence within the section of the source string that starts at the specified index and contains the specified number of elements.

System_CAPS_pubmethod IndexOf

Searches for the specified substring and returns the zero-based index of the first occurrence within the section of the source string that starts at the specified index and contains the specified number of elements using the specified CompareOptions value.

System_CAPS_pubmethod IsPrefix

Determines whether the specified source string starts with the specified prefix.

System_CAPS_pubmethod IsPrefix

Determines whether the specified source string starts with the specified prefix using the specified CompareOptions value.

System_CAPS_pubmethod System_CAPS_static IsSortable

Indicates whether a specified Unicode character is sortable.

System_CAPS_pubmethod System_CAPS_static IsSortable

Indicates whether a specified Unicode string is sortable.

System_CAPS_pubmethod IsSuffix

Determines whether the specified source string ends with the specified suffix.

System_CAPS_pubmethod IsSuffix

Determines whether the specified source string ends with the specified suffix using the specified CompareOptions value.

System_CAPS_pubmethod LastIndexOf

Searches for the specified character and returns the zero-based index of the last occurrence within the entire source string.

System_CAPS_pubmethod LastIndexOf

Searches for the specified character and returns the zero-based index of the last occurrence within the entire source string using the specified CompareOptions value.

System_CAPS_pubmethod LastIndexOf

Searches for the specified character and returns the zero-based index of the last occurrence within the section of the source string that extends from the beginning of the string to the specified index.

System_CAPS_pubmethod LastIndexOf

Searches for the specified character and returns the zero-based index of the last occurrence within the section of the source string that extends from the beginning of the string to the specified index using the specified CompareOptions value.

System_CAPS_pubmethod LastIndexOf

Searches for the specified character and returns the zero-based index of the last occurrence within the section of the source string that contains the specified number of elements and ends at the specified index.

System_CAPS_pubmethod LastIndexOf

Searches for the specified character and returns the zero-based index of the last occurrence within the section of the source string that contains the specified number of elements and ends at the specified index using the specified CompareOptions value.

System_CAPS_pubmethod LastIndexOf

Searches for the specified substring and returns the zero-based index of the last occurrence within the entire source string.

System_CAPS_pubmethod LastIndexOf

Searches for the specified substring and returns the zero-based index of the last occurrence within the entire source string using the specified CompareOptions value.

System_CAPS_pubmethod LastIndexOf

Searches for the specified substring and returns the zero-based index of the last occurrence within the section of the source string that extends from the beginning of the string to the specified index.

System_CAPS_pubmethod LastIndexOf

Searches for the specified substring and returns the zero-based index of the last occurrence within the section of the source string that extends from the beginning of the string to the specified index using the specified CompareOptions value.

System_CAPS_pubmethod LastIndexOf

Searches for the specified substring and returns the zero-based index of the last occurrence within the section of the source string that contains the specified number of elements and ends at the specified index.

System_CAPS_pubmethod LastIndexOf

Searches for the specified substring and returns the zero-based index of the last occurrence within the section of the source string that contains the specified number of elements and ends at the specified index using the specified CompareOptions value.

System_CAPS_protmethod MemberwiseClone

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethod ToString

Returns a string that represents the current CompareInfo object.(Overrides ObjectToString.)

NameDescription
System_CAPS_pubinterface System_CAPS_privmethod IDeserializationCallbackOnDeserialization

Runs when the entire object graph has been deserialized.

Conventions for comparing and sorting data vary from culture to culture. For example, sort order may be based on phonetics or on the visual representation of characters. In East Asian languages, characters are sorted by the stroke and radical of ideographs. Sorting also depends on the order languages and cultures use for the alphabet. For example, the Danish language has an "Æ" character that it sorts after "Z" in the alphabet. In addition, comparisons may be case-sensitive or case-insensitive, and casing rules may also differ by culture. The CompareInfo class is responsible for maintaining this culture-sensitive string comparison data and for performing culture-sensitive string operations.

Typically, you do not have to instantiate a CompareInfo object directly, because one is used implicitly by all non-ordinal string comparison operations, including calls to the StringCompare method. However, if you do want to retrieve a CompareInfo object, you can do it in one of these ways:

  • By retrieving the value of the property for a particular culture.

  • By calling the static GetCompareInfo method with a culture name. This allows for late-bound access to a CompareInfo object.

Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Comparison methods such as IndexOf and LastIndexOf do not consider such characters when they perform a culture-sensitive comparison. Ignorable characters include:

  • StringEmpty. Culture-sensitive comparison methods will always find an empty string at the beginning (index zero) of the string being searched.

  • A character or string consisting of characters with code points that are not considered in the operation because of comparison options, In particular, the CompareOptionsIgnoreNonSpace and CompareOptionsIgnoreSymbols options produce searches in which symbols and nonspacing combining characters are ignored.

  • A string with code points that have no linguistic significance. For example, a soft hyphen (U+00AD) is always ignored in a culture-sensitive string comparison.

If a security decision depends on a string comparison or a case change, you should use the property to ensure that the behavior is consistent, regardless of the culture settings of the operating system.

System_CAPS_noteNote

When possible, you should use 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.

The following example shows how the CompareInfo object associated with a CultureInfo object affects string comparison.

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
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
using namespace System;
using namespace System::Text;
using namespace System::Globalization;

int main()
{
    array<String^>^ sign = gcnew array<String^> { "<", "=", ">" };

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

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

    // Display the result using fr-FR Compare of Coté = coté.
    Console::WriteLine(L"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(L"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 = (gcnew CultureInfo("ja-JP"))->CompareInfo;
    Console::WriteLine(L"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
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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