NOTE: This API is now obsolete. The non-obsolete alternative is StringComparer.
Supplies a hash code for an object, using a hashing algorithm that ignores the case of strings.
Assembly: mscorlib (in mscorlib.dll)
<SerializableAttribute> _ <ObsoleteAttribute("Please use StringComparer instead.")> _ <ComVisibleAttribute(True)> _ Public Class CaseInsensitiveHashCodeProvider _ Implements IHashCodeProvider
Dim instance As CaseInsensitiveHashCodeProvider
[SerializableAttribute] [ObsoleteAttribute("Please use StringComparer instead.")] [ComVisibleAttribute(true)] public class CaseInsensitiveHashCodeProvider : IHashCodeProvider
[SerializableAttribute] [ObsoleteAttribute(L"Please use StringComparer instead.")] [ComVisibleAttribute(true)] public ref class CaseInsensitiveHashCodeProvider : IHashCodeProvider
public class CaseInsensitiveHashCodeProvider implements IHashCodeProvider
CaseInsensitiveHashCodeProvider implements the IHashCodeProvider interface supporting case-insensitive comparisons on strings, just as CaseInsensitiveComparer implements the IComparer interface supporting case-insensitive comparisons on strings.
The objects used as keys by a Hashtable are required to override the Object.GetHashCode method (or the IHashCodeProvider interface) and the Object.Equals method (or the IComparer interface). The implementation of both methods or interfaces must handle case sensitivity the same way; otherwise, the Hashtable might behave incorrectly. For example, when creating a Hashtable, you must use this class with the CaseInsensitiveComparer class or any case-insensitive IComparer implementation.
The following code example creates a case-sensitive hash table and a case-insensitive hash table and demonstrates the difference in their behavior, even if both contain the same elements.
Imports System Imports System.Collections Imports System.Globalization Public Class SamplesHashtable Public Shared Sub Main() ' Create a Hashtable using the default hash code provider and the default comparer. Dim myHT1 As New Hashtable() myHT1.Add("FIRST", "Hello") myHT1.Add("SECOND", "World") myHT1.Add("THIRD", "!") ' Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, ' based on the culture of the current thread. Dim myHT2 As New Hashtable(New CaseInsensitiveHashCodeProvider(), New CaseInsensitiveComparer()) myHT2.Add("FIRST", "Hello") myHT2.Add("SECOND", "World") myHT2.Add("THIRD", "!") ' Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, ' based on the InvariantCulture. Dim myHT3 As New Hashtable(CaseInsensitiveHashCodeProvider.DefaultInvariant, CaseInsensitiveComparer.DefaultInvariant) myHT3.Add("FIRST", "Hello") myHT3.Add("SECOND", "World") myHT3.Add("THIRD", "!") ' Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, ' based on the Turkish culture (tr-TR), where "I" is not the uppercase version of "i". Dim myCul As New CultureInfo("tr-TR") Dim myHT4 As New Hashtable(New CaseInsensitiveHashCodeProvider(myCul), New CaseInsensitiveComparer(myCul)) myHT4.Add("FIRST", "Hello") myHT4.Add("SECOND", "World") myHT4.Add("THIRD", "!") ' Search for a key in each hashtable. Console.WriteLine("first is in myHT1: {0}", myHT1.ContainsKey("first")) Console.WriteLine("first is in myHT2: {0}", myHT2.ContainsKey("first")) Console.WriteLine("first is in myHT3: {0}", myHT3.ContainsKey("first")) Console.WriteLine("first is in myHT4: {0}", myHT4.ContainsKey("first")) End Sub 'Main End Class 'SamplesHashtable 'This code produces the following output. Results vary depending on the system's culture settings. ' 'first is in myHT1: False 'first is in myHT2: True 'first is in myHT3: True 'first is in myHT4: False
using System; using System.Collections; using System.Globalization; public class SamplesHashtable { public static void Main() { // Create a Hashtable using the default hash code provider and the default comparer. Hashtable myHT1 = new Hashtable(); myHT1.Add("FIRST", "Hello"); myHT1.Add("SECOND", "World"); myHT1.Add("THIRD", "!"); // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, // based on the culture of the current thread. Hashtable myHT2 = new Hashtable( new CaseInsensitiveHashCodeProvider(), new CaseInsensitiveComparer() ); myHT2.Add("FIRST", "Hello"); myHT2.Add("SECOND", "World"); myHT2.Add("THIRD", "!"); // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, // based on the InvariantCulture. Hashtable myHT3 = new Hashtable( CaseInsensitiveHashCodeProvider.DefaultInvariant, CaseInsensitiveComparer.DefaultInvariant ); myHT3.Add("FIRST", "Hello"); myHT3.Add("SECOND", "World"); myHT3.Add("THIRD", "!"); // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, // based on the Turkish culture (tr-TR), where "I" is not the uppercase version of "i". CultureInfo myCul = new CultureInfo( "tr-TR" ); Hashtable myHT4 = new Hashtable( new CaseInsensitiveHashCodeProvider( myCul ), new CaseInsensitiveComparer( myCul ) ); myHT4.Add("FIRST", "Hello"); myHT4.Add("SECOND", "World"); myHT4.Add("THIRD", "!"); // Search for a key in each hashtable. Console.WriteLine( "first is in myHT1: {0}", myHT1.ContainsKey( "first" ) ); Console.WriteLine( "first is in myHT2: {0}", myHT2.ContainsKey( "first" ) ); Console.WriteLine( "first is in myHT3: {0}", myHT3.ContainsKey( "first" ) ); Console.WriteLine( "first is in myHT4: {0}", myHT4.ContainsKey( "first" ) ); } } /* This code produces the following output. Results vary depending on the system's culture settings. first is in myHT1: False first is in myHT2: True first is in myHT3: True first is in myHT4: False */
using namespace System; using namespace System::Collections; using namespace System::Globalization; int main() { // Create a Hashtable using the default hash code provider and the default comparer. Hashtable^ myHT1 = gcnew Hashtable; myHT1->Add( "FIRST", "Hello" ); myHT1->Add( "SECOND", "World" ); myHT1->Add( "THIRD", "!" ); // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, // based on the culture of the current thread. Hashtable^ myHT2 = gcnew Hashtable( gcnew CaseInsensitiveHashCodeProvider,gcnew CaseInsensitiveComparer ); myHT2->Add( "FIRST", "Hello" ); myHT2->Add( "SECOND", "World" ); myHT2->Add( "THIRD", "!" ); // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, // based on the InvariantCulture. Hashtable^ myHT3 = gcnew Hashtable( CaseInsensitiveHashCodeProvider::DefaultInvariant,CaseInsensitiveComparer::DefaultInvariant ); myHT3->Add( "FIRST", "Hello" ); myHT3->Add( "SECOND", "World" ); myHT3->Add( "THIRD", "!" ); // Create a Hashtable using a case-insensitive code provider and a case-insensitive comparer, // based on the Turkish culture (tr-TR), where "I" is not the uppercase version of "i". CultureInfo^ myCul = gcnew CultureInfo( "tr-TR" ); Hashtable^ myHT4 = gcnew Hashtable( gcnew CaseInsensitiveHashCodeProvider( myCul ),gcnew CaseInsensitiveComparer( myCul ) ); myHT4->Add( "FIRST", "Hello" ); myHT4->Add( "SECOND", "World" ); myHT4->Add( "THIRD", "!" ); // Search for a key in each hashtable. Console::WriteLine( "first is in myHT1: {0}", myHT1->ContainsKey( "first" ) ); Console::WriteLine( "first is in myHT2: {0}", myHT2->ContainsKey( "first" ) ); Console::WriteLine( "first is in myHT3: {0}", myHT3->ContainsKey( "first" ) ); Console::WriteLine( "first is in myHT4: {0}", myHT4->ContainsKey( "first" ) ); } /* This code produces the following output. Results vary depending on the system's culture settings. first is in myHT1: False first is in myHT2: True first is in myHT3: True first is in myHT4: False */
System.Collections.CaseInsensitiveHashCodeProvider
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 1.1, 1.0Obsolete (compiler warning) in 3.5
Obsolete (compiler warning) in 3.5 SP1
Obsolete (compiler warning) in 3.0
Obsolete (compiler warning) in 3.0 SP1
Obsolete (compiler warning) in 3.0 SP2
Obsolete (compiler warning) in 2.0
Obsolete (compiler warning) in 2.0 SP1
Obsolete (compiler warning) in 2.0 SP2
.NET Compact Framework
Supported in: 1.0Obsolete (compiler warning) in 3.5
Obsolete (compiler warning) in 2.0
XNA Framework
Obsolete (compiler warning) in 3.0Obsolete (compiler warning) in 2.0
Obsolete (compiler warning) in 1.0