String.ToLower Méthode

Définition

Retourne une copie de cette chaîne convertie en minuscules.Returns a copy of this string converted to lowercase.

Surcharges

ToLower(CultureInfo)

Retourne une copie de cette chaîne en minuscules, à l'aide des règles de casse de la culture spécifiée.Returns a copy of this string converted to lowercase, using the casing rules of the specified culture.

ToLower()

Retourne une copie de cette chaîne convertie en minuscules.Returns a copy of this string converted to lowercase.

ToLower(CultureInfo)

Retourne une copie de cette chaîne en minuscules, à l'aide des règles de casse de la culture spécifiée.Returns a copy of this string converted to lowercase, using the casing rules of the specified culture.

public:
 System::String ^ ToLower(System::Globalization::CultureInfo ^ culture);
public string ToLower (System.Globalization.CultureInfo culture);
member this.ToLower : System.Globalization.CultureInfo -> string
Public Function ToLower (culture As CultureInfo) As String

Paramètres

culture
CultureInfo

Objet qui fournit les règles de casse propres à la culture.An object that supplies culture-specific casing rules.

Retours

Équivalent en minuscules de la chaîne actuelle.The lowercase equivalent of the current string.

Exceptions

culture a la valeur null.culture is null.

Exemples

L’exemple suivant convertit deux chaînes de caractères majuscules en caractères minuscules à l’aide des cultures Anglais-États-Unis et turc-Turquie, puis compare les chaînes minuscules.The following example converts two strings of uppercase characters to lowercase characters using the English-United States and Turkish-Turkey cultures, then compares the lowercase strings. Les chaînes en majuscules sont identiques, sauf que pour chaque occurrence de la lettre majuscule Unicode latine I dans une chaîne, l’autre chaîne contient la lettre majuscule latine I avec point ci-dessus.The uppercase strings are identical except that for each occurrence of the Unicode LATIN CAPITAL LETTER I in one string, the other string contains LATIN CAPITAL LETTER I WITH DOT ABOVE.

// Sample for String::ToLower(CultureInfo)
using namespace System;
using namespace System::Globalization;
void CodePoints( String^ title, String^ s )
{
   Console::Write( "{0}The code points in {1} are: {0}", Environment::NewLine, title );
   System::Collections::IEnumerator^ myEnum = s->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      UInt16 u =  safe_cast<Char>(myEnum->Current);
      Console::Write( "{0:x4} ", u );
   }

   Console::WriteLine();
}

int main()
{
   String^ str1 = "INDIGO";
   
   // str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE).
   array<Char>^temp = {L'\u0130',L'N',L'D',L'\u0130',L'G',L'O'};
   String^ str2 = gcnew String( temp );
   String^ str3;
   String^ str4;
   Console::WriteLine();
   Console::WriteLine( "str1 = '{0}'", str1 );
   Console::WriteLine();
   Console::WriteLine( "str1 is {0} to str2.", ((0 == String::CompareOrdinal( str1, str2 )) ? (String^)"equal" : "not equal") );
   CodePoints( "str1", str1 );
   CodePoints( "str2", str2 );
   Console::WriteLine();
   
   // str3 is a lower case copy of str2, using English-United States culture.
   Console::WriteLine( "str3 = Lower case copy of str2 using English-United States culture." );
   str3 = str2->ToLower( gcnew CultureInfo( "en-US",false ) );
   
   // str4 is a lower case copy of str2, using Turkish-Turkey culture.
   Console::WriteLine( "str4 = Lower case copy of str2 using Turkish-Turkey culture." );
   str4 = str2->ToLower( gcnew CultureInfo( "tr-TR",false ) );
   
   // Compare the code points in str3 and str4.
   Console::WriteLine();
   Console::WriteLine( "str3 is {0} to str4.", ((0 == String::CompareOrdinal( str3, str4 )) ? (String^)"equal" : "not equal") );
   CodePoints( "str3", str3 );
   CodePoints( "str4", str4 );
}

/*
This example produces the following results:

str1 = 'INDIGO'

str1 is not equal to str2.

The code points in str1 are:
0049 004e 0044 0049 0047 004f

The code points in str2 are:
0130 004e 0044 0130 0047 004f

str3 = Lower case copy of str2 using English-United States culture.
str4 = Lower case copy of str2 using Turkish-Turkey culture.

str3 is equal to str4.

The code points in str3 are:
0069 006e 0064 0069 0067 006f

The code points in str4 are:
0069 006e 0064 0069 0067 006f
*/
// Sample for String.ToLower(CultureInfo)

using System;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    String str1 = "INDIGO";
    // str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE).
    String str2 = new String(new Char[] {'\u0130', 'N', 'D', '\u0130', 'G', 'O'});
    String str3, str4;

    Console.WriteLine();
    Console.WriteLine("str1 = '{0}'", str1);

    Console.WriteLine();
    Console.WriteLine("str1 is {0} to str2.", 
         ((0 == String.CompareOrdinal(str1, str2)) ? "equal" : "not equal"));
    CodePoints("str1", str1);
    CodePoints("str2", str2);

    Console.WriteLine();
    // str3 is a lower case copy of str2, using English-United States culture.
    Console.WriteLine("str3 = Lower case copy of str2 using English-United States culture.");
    str3 = str2.ToLower(new CultureInfo("en-US", false));

    // str4 is a lower case copy of str2, using Turkish-Turkey culture.
    Console.WriteLine("str4 = Lower case copy of str2 using Turkish-Turkey culture.");
    str4 = str2.ToLower(new CultureInfo("tr-TR", false));

    // Compare the code points in str3 and str4.
    Console.WriteLine();
    Console.WriteLine("str3 is {0} to str4.", 
         ((0 == String.CompareOrdinal(str3, str4)) ? "equal" : "not equal"));
    CodePoints("str3", str3);
    CodePoints("str4", str4);
    }

    public static void CodePoints(String title, String s)
    {
    Console.Write("{0}The code points in {1} are: {0}", Environment.NewLine, title);
    foreach (ushort u in s)
      Console.Write("{0:x4} ", u);
    Console.WriteLine();
    }
}
/*
This example produces the following results:

str1 = 'INDIGO'

str1 is not equal to str2.

The code points in str1 are:
0049 004e 0044 0049 0047 004f

The code points in str2 are:
0130 004e 0044 0130 0047 004f

str3 = Lower case copy of str2 using English-United States culture.
str4 = Lower case copy of str2 using Turkish-Turkey culture.

str3 is equal to str4.

The code points in str3 are:
0069 006e 0064 0069 0067 006f

The code points in str4 are:
0069 006e 0064 0069 0067 006f
*/
' Sample for String.ToLower(CultureInfo)
Imports System.Globalization

Class Sample
   Public Shared Sub Main()
      Dim str1 As [String] = "INDIGO"
      ' str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE).
      Dim str2 As New [String](New [Char]() {ChrW(&H0130), "N"c, "D"c, ChrW(&H0130), "G"c, "O"c})
      Dim str3, str4 As [String]

      Console.WriteLine()
      Console.WriteLine("str1 = '{0}'", str1)

      Console.WriteLine()
      Console.WriteLine("str1 is {0} to str2.", _
                         IIf(0 = [String].CompareOrdinal(str1, str2), "equal", "not equal"))
      CodePoints("str1", str1)
      CodePoints("str2", str2)

      Console.WriteLine()
      ' str3 is a lower case copy of str2, using English-United States culture.
      Console.WriteLine("str3 = Lower case copy of str2 using English-United States culture.")
      str3 = str2.ToLower(New CultureInfo("en-US", False))

      ' str4 is a lower case copy of str2, using Turkish-Turkey culture.
      Console.WriteLine("str4 = Lower case copy of str2 using Turkish-Turkey culture.")
      str4 = str2.ToLower(New CultureInfo("tr-TR", False))

      ' Compare the code points in str3 and str4.
      Console.WriteLine()
      Console.WriteLine("str3 is {0} to str4.", _
                         IIf(0 = [String].CompareOrdinal(str3, str4), "equal", "not equal"))
      CodePoints("str3", str3)
      CodePoints("str4", str4)
   End Sub

   Public Shared Sub CodePoints(title As [String], s As [String])
      Console.Write("{0}The code points in {1} are: {0}", Environment.NewLine, title)
      Dim c As Char
      For Each c In  s
         Console.Write("{0:x4} ", AscW(c))
      Next c
      Console.WriteLine()
   End Sub
End Class
'
'str1 = 'INDIGO'
'
'str1 is not equal to str2.
'
'The code points in str1 are:
'0049 004e 0044 0049 0047 004f
'
'The code points in str2 are:
'0130 004e 0044 0130 0047 004f
'
'str3 = Lower case copy of str2 using English-United States culture.
'str4 = Lower case copy of str2 using Turkish-Turkey culture.
'
'str3 is equal to str4.
'
'The code points in str3 are:
'0069 006e 0064 0069 0067 006f
'
'The code points in str4 are:
'0069 006e 0064 0069 0067 006f

Remarques

Les règles de casse de la culture spécifiée par le paramètre culture déterminent la façon dont la casse de la chaîne est modifiée.The casing rules of the culture specified by the culture parameter determine the way the case of the string is changed.

Notes

Cette méthode ne modifie pas la valeur de l’instance actuelle.This method does not modify the value of the current instance. Au lieu de cela, elle retourne une nouvelle chaîne dans laquelle tous les caractères de l’instance actuelle sont convertis en minuscules.Instead, it returns a new string in which all characters in the current instance are converted to lowercase.

Considérations relatives à la sécuritéSecurity Considerations

Si vous transmettez à la méthode ToLower(CultureInfo) un objet CultureInfo autre que CultureInfo.InvariantCulture, l’opération de casse prendra en compte des règles spécifiques à la culture.If you pass the ToLower(CultureInfo) method a CultureInfo object other than CultureInfo.InvariantCulture, the casing operation will take culture-specific rules into account. Si vous avez besoin de la version en minuscules ou en majuscules d’un identificateur de système d’exploitation, par exemple un nom de fichier, un canal nommé ou une clé de Registre, utilisez la méthode ToLowerInvariant ou ToUpperInvariant.If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant method. Cela produit le même résultat dans chaque culture et s’exécute plus efficacement.This produces the same result in every culture and performs more efficiently.

Voir aussi

ToLower()

Retourne une copie de cette chaîne convertie en minuscules.Returns a copy of this string converted to lowercase.

public:
 System::String ^ ToLower();
public string ToLower ();
member this.ToLower : unit -> string
Public Function ToLower () As String

Retours

Chaîne en minuscules.A string in lowercase.

Exemples

L’exemple suivant convertit plusieurs chaînes de casse mixte en minuscules.The following example converts several mixed case strings to lowercase.

using namespace System;
using namespace System::Collections;
int main()
{
   array<String^>^info = {"Name","Title","Age","Location","Gender"};
   Console::WriteLine( "The initial values in the array are:" );
   IEnumerator^ myEnum = info->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      String^ s = safe_cast<String^>(myEnum->Current);
      Console::WriteLine( s );
   }

   Console::WriteLine( " {0}The lowercase of these values is:", Environment::NewLine );
   IEnumerator^ myEnum1 = info->GetEnumerator();
   while ( myEnum1->MoveNext() )
   {
      String^ s = safe_cast<String^>(myEnum1->Current);
      Console::WriteLine( s->ToLower() );
   }

   Console::WriteLine( " {0}The uppercase of these values is:", Environment::NewLine );
   IEnumerator^ myEnum2 = info->GetEnumerator();
   while ( myEnum2->MoveNext() )
   {
      String^ s = safe_cast<String^>(myEnum2->Current);
      Console::WriteLine( s->ToUpper() );
   }
}
// The example displays the following output:
//       The initial values in the array are:
//       Name
//       Title
//       Age
//       Location
//       Gender
//       
//       The lowercase of these values is:
//       name
//       title
//       age
//       location
//       gender
//       
//       The uppercase of these values is:
//       NAME
//       TITLE
//       AGE
//       LOCATION
//       GENDER
using System;

public class ToLowerTest {
    public static void Main() {

        string [] info = {"Name", "Title", "Age", "Location", "Gender"};

        Console.WriteLine("The initial values in the array are:");
        foreach (string s in info)
            Console.WriteLine(s);

        Console.WriteLine("{0}The lowercase of these values is:", Environment.NewLine);        

        foreach (string s in info)
            Console.WriteLine(s.ToLower());

        Console.WriteLine("{0}The uppercase of these values is:", Environment.NewLine);        

        foreach (string s in info)
            Console.WriteLine(s.ToUpper());
    }
}
// The example displays the following output:
//       The initial values in the array are:
//       Name
//       Title
//       Age
//       Location
//       Gender
//       
//       The lowercase of these values is:
//       name
//       title
//       age
//       location
//       gender
//       
//       The uppercase of these values is:
//       NAME
//       TITLE
//       AGE
//       LOCATION
//       GENDER
Public Class ToLowerTest
    
    Public Shared Sub Main()
        Dim info As String() = {"Name", "Title", "Age", "Location", "Gender"}
        
        Console.WriteLine("The initial values in the array are:")

        Dim s As String
        For Each s In info
            Console.WriteLine(s)
        Next 

        Console.WriteLine("{0}The lowercase of these values is:", Environment.NewLine)

        For Each s In info
            Console.WriteLine(s.ToLower())
        Next 

        Console.WriteLine("{0}The uppercase of these values is:", Environment.NewLine)

        For Each s In  info
            Console.WriteLine(s.ToUpper())
        Next 
    End Sub 
End Class 
' The example displays the following output:
'       The initial values in the array are:
'       Name
'       Title
'       Age
'       Location
'       Gender
'       
'       The lowercase of these values is:
'       name
'       title
'       age
'       location
'       gender
'       
'       The uppercase of these values is:
'       NAME
'       TITLE
'       AGE
'       LOCATION
'       GENDER

Remarques

Cette méthode prend en compte les règles de casse de la culture actuelle.This method takes into account the casing rules of the current culture.

Notes

Cette méthode ne modifie pas la valeur de l’instance actuelle.This method does not modify the value of the current instance. Au lieu de cela, elle retourne une nouvelle chaîne dans laquelle tous les caractères de l’instance actuelle sont convertis en minuscules.Instead, it returns a new string in which all characters in the current instance are converted to lowercase.

Considérations relatives à la sécuritéSecurity Considerations

L’opération de casse qui résulte de l’appel de la méthode ToLower() prend en compte les conventions de casse de la culture actuelle.The casing operation that results from calling the ToLower() method takes the casing conventions of the current culture into account. Si vous avez besoin de la version en minuscules ou en majuscules d’un identificateur de système d’exploitation, par exemple un nom de fichier, un canal nommé ou une clé de Registre, utilisez les méthodes ToLowerInvariant ou ToUpperInvariant.If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant methods. Cela produit le même résultat dans chaque culture (contrairement à la méthode ToLower()) et s’exécute plus efficacement.This produces the same result in every culture (unlike the ToLower() method) and performs more efficiently.

Notes pour les appelants

Comme expliqué dans meilleures pratiques pour l’utilisation de chaînes, nous vous recommandons d’éviter d’appeler des méthodes de casse de chaîne qui substituent des valeurs par défaut et d’appeler à la place des méthodes qui requièrent que des paramètres soient explicitement spécifiés.As explained in Best Practices for Using Strings, we recommend that you avoid calling string casing methods that substitute default values and instead call methods that require parameters to be explicitly specified. Pour convertir un caractère en minuscules à l’aide des conventions de casse de la culture actuelle, appelez la surcharge de méthode ToLower(CultureInfo) avec la valeur CurrentCulture pour son paramètre culture.To convert a character to lowercase by using the casing conventions of the current culture, call the ToLower(CultureInfo) method overload with a value of CurrentCulture for its culture parameter.

Voir aussi

S’applique à