CaseInsensitiveComparer.DefaultInvariant Property
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Gets an instance of CaseInsensitiveComparer that is associated with InvariantCulture and that is always available.
public:
static property System::Collections::CaseInsensitiveComparer ^ DefaultInvariant { System::Collections::CaseInsensitiveComparer ^ get(); };C#
public static System.Collections.CaseInsensitiveComparer DefaultInvariant { get; }static member DefaultInvariant : System.Collections.CaseInsensitiveComparerPublic Shared ReadOnly Property DefaultInvariant As CaseInsensitiveComparerAn instance of CaseInsensitiveComparer that is associated with InvariantCulture.
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.
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
*/
C#
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
*/
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
End Class
'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
Comparison procedures use the CultureInfo.InvariantCulture to determine the sort order and casing rules. String comparisons might have different results depending on the culture. For more information on culture-specific comparisons, see the System.Globalization namespace and Globalization and Localization.
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
| UWP | 10.0 |
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