CaseInsensitiveComparer Constructors
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Initializes a new instance of the CaseInsensitiveComparer class.
| CaseInsensitiveComparer() |
Initializes a new instance of the CaseInsensitiveComparer class using the CurrentCulture of the current thread. |
| CaseInsensitiveComparer(CultureInfo) |
Initializes a new instance of the CaseInsensitiveComparer class using the specified CultureInfo. |
- Source:
- CaseInsensitiveComparer.cs
- Source:
- CaseInsensitiveComparer.cs
- Source:
- CaseInsensitiveComparer.cs
Initializes a new instance of the CaseInsensitiveComparer class using the CurrentCulture of the current thread.
public:
CaseInsensitiveComparer();C#
public CaseInsensitiveComparer();Public Sub New ()Examples
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
Remarks
When the CaseInsensitiveComparer instance is created using this constructor, the Thread.CurrentCulture of the current thread is saved. Comparison procedures use the saved culture to determine the sort order and casing rules; therefore, 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.
See also
- CurrentCulture
- CultureInfo
- CompareInfo
- Performing Culture-Insensitive String Operations in Collections
Applies to
.NET 10 and other versions
| 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 |
- Source:
- CaseInsensitiveComparer.cs
- Source:
- CaseInsensitiveComparer.cs
- Source:
- CaseInsensitiveComparer.cs
Initializes a new instance of the CaseInsensitiveComparer class using the specified CultureInfo.
public:
CaseInsensitiveComparer(System::Globalization::CultureInfo ^ culture);C#
public CaseInsensitiveComparer(System.Globalization.CultureInfo culture);new System.Collections.CaseInsensitiveComparer : System.Globalization.CultureInfo -> System.Collections.CaseInsensitiveComparerPublic Sub New (culture As CultureInfo)Parameters
- culture
- CultureInfo
The CultureInfo to use for the new CaseInsensitiveComparer.
Exceptions
culture is null.
Examples
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
Remarks
Comparison procedures use the specified System.Globalization.CultureInfo 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.
See also
Applies to
.NET 10 and other versions
| 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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