String.IndexOf String.IndexOf String.IndexOf String.IndexOf Method

Definição

Relata o índice de base zero da primeira ocorrência de uma cadeia de caracteres ou um caractere Unicode especificado nesta instância.Reports the zero-based index of the first occurrence of a specified Unicode character or string within this instance. O método retorna -1 caso o caractere ou a cadeia de caracteres não seja encontrado nessa instância.The method returns -1 if the character or string is not found in this instance.

Sobrecargas

IndexOf(String, Int32, Int32) IndexOf(String, Int32, Int32) IndexOf(String, Int32, Int32) IndexOf(String, Int32, Int32)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada nessa instância.Reports the zero-based index of the first occurrence of the specified string in this instance. A pesquisa é iniciada em uma posição de caractere especificada e examina um número especificado de posições de caracteres.The search starts at a specified character position and examines a specified number of character positions.

IndexOf(String, Int32, Int32, StringComparison) IndexOf(String, Int32, Int32, StringComparison) IndexOf(String, Int32, Int32, StringComparison) IndexOf(String, Int32, Int32, StringComparison)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada no objeto String atual.Reports the zero-based index of the first occurrence of the specified string in the current String object. Parâmetros especificam a posição inicial de pesquisa na cadeia de caracteres de atual, o número de caracteres na cadeia de caracteres atual para pesquisar e o tipo de pesquisa a ser usado para a cadeia de caracteres especificada.Parameters specify the starting search position in the current string, the number of characters in the current string to search, and the type of search to use for the specified string.

IndexOf(String, Int32, StringComparison) IndexOf(String, Int32, StringComparison) IndexOf(String, Int32, StringComparison) IndexOf(String, Int32, StringComparison)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada no objeto String atual.Reports the zero-based index of the first occurrence of the specified string in the current String object. Os parâmetros especificam a posição de pesquisa inicial na cadeia de caracteres atual e o tipo de pesquisa a ser usado para a cadeia de caracteres especificada.Parameters specify the starting search position in the current string and the type of search to use for the specified string.

IndexOf(Char, Int32, Int32) IndexOf(Char, Int32, Int32) IndexOf(Char, Int32, Int32) IndexOf(Char, Int32, Int32)

Relata o índice baseado em zero da primeira ocorrência do caractere especificado nessa instância.Reports the zero-based index of the first occurrence of the specified character in this instance. A pesquisa é iniciada em uma posição de caractere especificada e examina um número especificado de posições de caracteres.The search starts at a specified character position and examines a specified number of character positions.

IndexOf(String, StringComparison) IndexOf(String, StringComparison) IndexOf(String, StringComparison) IndexOf(String, StringComparison)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada no objeto String atual.Reports the zero-based index of the first occurrence of the specified string in the current String object. Um parâmetro especifica o tipo de pesquisa a ser usado para a cadeia de caracteres especificada.A parameter specifies the type of search to use for the specified string.

IndexOf(Char, StringComparison) IndexOf(Char, StringComparison) IndexOf(Char, StringComparison) IndexOf(Char, StringComparison)

Relata o índice baseado em zero da primeira ocorrência do caractere Unicode especificado na cadeia de caracteres.Reports the zero-based index of the first occurrence of the specified Unicode character in this string. Um parâmetro especifica o tipo de pesquisa a ser usado para o caractere especificado.A parameter specifies the type of search to use for the specified character.

IndexOf(Char, Int32) IndexOf(Char, Int32) IndexOf(Char, Int32) IndexOf(Char, Int32)

Relata o índice baseado em zero da primeira ocorrência do caractere Unicode especificado na cadeia de caracteres.Reports the zero-based index of the first occurrence of the specified Unicode character in this string. A pesquisa é iniciada em uma posição de caractere especificada.The search starts at a specified character position.

IndexOf(String) IndexOf(String) IndexOf(String) IndexOf(String)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada nessa instância.Reports the zero-based index of the first occurrence of the specified string in this instance.

IndexOf(Char) IndexOf(Char) IndexOf(Char) IndexOf(Char)

Relata o índice baseado em zero da primeira ocorrência do caractere Unicode especificado na cadeia de caracteres.Reports the zero-based index of the first occurrence of the specified Unicode character in this string.

IndexOf(String, Int32) IndexOf(String, Int32) IndexOf(String, Int32) IndexOf(String, Int32)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada nessa instância.Reports the zero-based index of the first occurrence of the specified string in this instance. A pesquisa é iniciada em uma posição de caractere especificada.The search starts at a specified character position.

IndexOf(String, Int32, Int32) IndexOf(String, Int32, Int32) IndexOf(String, Int32, Int32) IndexOf(String, Int32, Int32)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada nessa instância.Reports the zero-based index of the first occurrence of the specified string in this instance. A pesquisa é iniciada em uma posição de caractere especificada e examina um número especificado de posições de caracteres.The search starts at a specified character position and examines a specified number of character positions.

public:
 int IndexOf(System::String ^ value, int startIndex, int count);
public int IndexOf (string value, int startIndex, int count);
member this.IndexOf : string * int * int -> int
Public Function IndexOf (value As String, startIndex As Integer, count As Integer) As Integer

Parâmetros

value
String String String String

A cadeia de caracteres a ser buscada.The string to seek.

startIndex
Int32 Int32 Int32 Int32

A posição inicial da pesquisa.The search starting position.

count
Int32 Int32 Int32 Int32

O número de posições de caractere a serem examinadas.The number of character positions to examine.

Retornos

A posição de índice baseado em zero do value do início da instância atual se essa cadeia de caracteres for encontrada; caso contrário, -1.The zero-based index position of value from the start of the current instance if that string is found, or -1 if it is not. Se value for Empty, o valor retornado será startIndex.If value is Empty, the return value is startIndex.

Exceções

count ou startIndex é negativo.count or startIndex is negative.

- ou --or- startIndex é maior que o tamanho da cadeia de caracteres.startIndex is greater than the length of this string.

- ou --or- count é maior que o tamanho da cadeia de caracteres menos startIndex.count is greater than the length of this string minus startIndex.

Exemplos

O exemplo a seguir localiza o índice de todas as ocorrências da cadeia de caracteres "He" em uma subcadeia de caracteres de outra cadeia.The following example finds the index of all occurrences of the string "he" within a substring of another string. Observe que o número de caracteres a serem pesquisados deve ser recalculado para cada iteração de pesquisa.Note that the number of characters to be searched must be recalculated for each search iteration.

// Sample for String::IndexOf(String, Int32, Int32)
using namespace System;
int main()
{
   String^ br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-";
   String^ br2 = "0123456789012345678901234567890123456789012345678901234567890123456";
   String^ str = "Now is the time for all good men to come to the aid of their party.";
   int start;
   int at;
   int end;
   int count;
   end = str->Length;
   start = end / 2;
   Console::WriteLine();
   Console::WriteLine( "All occurrences of 'he' from position {0} to {1}.", start, end - 1 );
   Console::WriteLine( "{1}{0}{2}{0}{3}{0}", Environment::NewLine, br1, br2, str );
   Console::Write( "The string 'he' occurs at position(s): " );
   count = 0;
   at = 0;
   while ( (start <= end) && (at > -1) )
   {
      
      // start+count must be a position within -str-.
      count = end - start;
      at = str->IndexOf( "he", start, count );
      if ( at == -1 )
            break;

      Console::Write( "{0} ", at );
      start = at + 1;
   }

   Console::WriteLine();
}

/*
This example produces the following results:

All occurrences of 'he' from position 33 to 66.
0----+----1----+----2----+----3----+----4----+----5----+----6----+-
0123456789012345678901234567890123456789012345678901234567890123456
Now is the time for all good men to come to the aid of their party.

The string 'he' occurs at position(s): 45 56

*/
string br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+---";
string br2 = "012345678901234567890123456789012345678901234567890123456789012345678";
string str = "Now is the time for all good men to come to the aid of their country.";
int start;
int at;
int end;
int count;

end = str.Length;
start = end/2;
Console.WriteLine();
Console.WriteLine("All occurrences of 'he' from position {0} to {1}.", start, end-1);
Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str);
Console.Write("The string 'he' occurs at position(s): ");

count = 0;
at = 0;
while((start <= end) && (at > -1))
{
    // start+count must be a position within -str-.
    count = end - start;
    at = str.IndexOf("he", start, count);
    if (at == -1) break;
    Console.Write("{0} ", at);
    start = at+1;
}
Console.WriteLine();

/*
This example produces the following results:

All occurrences of 'he' from position 34 to 68.
0----+----1----+----2----+----3----+----4----+----5----+----6----+---
012345678901234567890123456789012345678901234567890123456789012345678
Now is the time for all good men to come to the aid of their country.

The string 'he' occurs at position(s): 45 56 

*/
' Sample for String.IndexOf(String, Int32, Int32)
Imports System

Class Sample
   
   Public Shared Sub Main()
      
      Dim br1 As String = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-"
      Dim br2 As String = "0123456789012345678901234567890123456789012345678901234567890123456"
      Dim str As String = "Now is the time for all good men to come to the aid of their party."
      Dim start As Integer
      Dim at As Integer
      Dim [end] As Integer
      Dim count As Integer
      
      [end] = str.Length
      start = [end] / 2
      Console.WriteLine()
      Console.WriteLine("All occurrences of 'he' from position {0} to {1}.", start, [end] - 1)
      Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str)
      Console.Write("The string 'he' occurs at position(s): ")
      
      count = 0
      at = 0
      While start <= [end] AndAlso at > - 1
         ' start+count must be a position within -str-.
         count = [end] - start
         at = str.IndexOf("he", start, count)
         If at = - 1 Then
            Exit While
         End If
         Console.Write("{0} ", at)
         start = at + 1
      End While
      Console.WriteLine()
   End Sub 'Main
End Class 'Sample
'
'This example produces the following results:
'
'All occurrences of 'he' from position 33 to 66.
'0----+----1----+----2----+----3----+----4----+----5----+----6----+-
'0123456789012345678901234567890123456789012345678901234567890123456
'Now is the time for all good men to come to the aid of their party.
'
'The string 'he' occurs at position(s): 45 56
'
'

Comentários

A numeração de índice começa em 0 (zero).Index numbering starts from 0 (zero). O parâmetro startIndex pode variar de 0 ao tamanho da instância da cadeia de caracteres.The startIndex parameter can range from 0 to the length of the string instance.

Este método executa uma pesquisa de palavra (diferencia maiúsculas de minúsculas e sensível à cultura) usando a cultura atual.This method performs a word (case-sensitive and culture-sensitive) search using the current culture. A pesquisa começa em startIndex e continua em startIndex + count -1.The search begins at startIndex and continues to startIndex + count -1. O caractere em startIndex + nãoestáincluído napesquisacount .The character at startIndex + count is not included in the search.

Conjuntos de caracteres incluem caracteres ignoráveis, que são caracteres que não são considerados ao durante a realização de uma comparação linguística ou sensível à cultura.Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Em uma pesquisa sensível à cultura, caso value contenha um caractere ignorável, o resultado é equivalente à pesquisa com esse caractere removido.In a culture-sensitive search, if value contains an ignorable character, the result is equivalent to searching with that character removed. Se value consistir apenas em um ou mais caracteres ignoráveis, IndexOf(String, Int32, Int32) o método sempre startIndexretornará, que é a posição do caractere na qual a pesquisa começa.If value consists only of one or more ignorable characters, the IndexOf(String, Int32, Int32) method always returns startIndex, which is the character position at which the search begins. No exemplo a seguir, o IndexOf(String, Int32, Int32) método é usado para localizar a posição de um hífen flexível (U + 00AD) seguido por um "m" começando no terceiro até sexto posições de caractere em duas cadeias de caracteres.In the following example, the IndexOf(String, Int32, Int32) method is used to find the position of a soft hyphen (U+00AD) followed by an "m" starting in the third through sixth character positions in two strings. Apenas uma das cadeias de caracteres contém a subcadeia de caracteres necessária.Only one of the strings contains the required substring. Se o exemplo for executado no .NET Framework 4.NET Framework 4 ou posterior, em ambos os casos, como o hífen suave é um caractere ignorável, o método retornará o índice de "m" na cadeia de caracteres quando ele executar uma comparação sensível à cultura.If the example is run on the .NET Framework 4.NET Framework 4 or later, in both cases, because the soft hyphen is an ignorable character, the method returns the index of "m" in the string when it performs a culture-sensitive comparison. No caso da primeira cadeia de caracteres, que inclui o hífen condicional seguido de um "m", o método não retorna o índice do hífen virtual, mas retorna o índice do "m".Note that in the case of the first string, which includes the soft hyphen followed by an "m", the method fails to return the index of the soft hyphen but instead returns the index of the "m".

using System;

public class Example
{
    public static void Main()
    {
        string searchString = "\u00ADm";
        string s1 = "ani\u00ADmal" ;
        string s2 = "animal";

        Console.WriteLine(s1.IndexOf(searchString, 2, 4));
        Console.WriteLine(s2.IndexOf(searchString, 2, 4));

        // The example displays the following output:
        //       4
        //       3
    }
}
Module Example
   Public Sub Main()
      Dim searchString As String = Chrw(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"

      Console.WriteLine(s1.IndexOf(searchString, 2, 4))
      Console.WriteLine(s2.IndexOf(searchString, 2, 4))
   End Sub
End Module
' The example displays the following output:
'       4
'       3

Notas aos Chamadores

Conforme explicado nas práticas recomendadas para usar cadeias decaracteres, é recomendável evitar a chamada de métodos de comparação de cadeia que substituem valores padrão e, em vez disso, chamam métodos que exigem que os parâmetros sejam especificados explicitamente.As explained in Best Practices for Using Strings, we recommend that you avoid calling string comparison methods that substitute default values and instead call methods that require parameters to be explicitly specified. Para usar as regras de comparação da cultura atual para executar essa operação, chame a IndexOf(String, Int32, Int32, StringComparison) sobrecarga do método com um valor CurrentCulture de para comparisonType seu parâmetro.To use the comparison rules of the current culture to perform this operation, call the IndexOf(String, Int32, Int32, StringComparison) method overload with a value of CurrentCulture for its comparisonType parameter.

Veja também

IndexOf(String, Int32, Int32, StringComparison) IndexOf(String, Int32, Int32, StringComparison) IndexOf(String, Int32, Int32, StringComparison) IndexOf(String, Int32, Int32, StringComparison)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada no objeto String atual.Reports the zero-based index of the first occurrence of the specified string in the current String object. Parâmetros especificam a posição inicial de pesquisa na cadeia de caracteres de atual, o número de caracteres na cadeia de caracteres atual para pesquisar e o tipo de pesquisa a ser usado para a cadeia de caracteres especificada.Parameters specify the starting search position in the current string, the number of characters in the current string to search, and the type of search to use for the specified string.

public:
 int IndexOf(System::String ^ value, int startIndex, int count, StringComparison comparisonType);
public int IndexOf (string value, int startIndex, int count, StringComparison comparisonType);
member this.IndexOf : string * int * int * StringComparison -> int
Public Function IndexOf (value As String, startIndex As Integer, count As Integer, comparisonType As StringComparison) As Integer

Parâmetros

value
String String String String

A cadeia de caracteres a ser buscada.The string to seek.

startIndex
Int32 Int32 Int32 Int32

A posição inicial da pesquisa.The search starting position.

count
Int32 Int32 Int32 Int32

O número de posições de caractere a serem examinadas.The number of character positions to examine.

comparisonType
StringComparison StringComparison StringComparison StringComparison

Um dos valores de enumeração que especifica as regras para a pesquisa.One of the enumeration values that specifies the rules for the search.

Retornos

A posição de índice baseado em zero do parâmetro value do início da instância atual se essa cadeia de caracteres for encontrada; caso contrário, -1.The zero-based index position of the value parameter from the start of the current instance if that string is found, or -1 if it is not. Se value for Empty, o valor retornado será startIndex.If value is Empty, the return value is startIndex.

Exceções

count ou startIndex é negativo.count or startIndex is negative.

- ou --or- startIndex é maior que o tamanho desta instância.startIndex is greater than the length of this instance.

- ou --or- count é maior que o tamanho da cadeia de caracteres menos startIndex.count is greater than the length of this string minus startIndex.

comparisonType não é um valor StringComparison válido.comparisonType is not a valid StringComparison value.

Exemplos

O exemplo a seguir demonstra três sobrecargas do IndexOf método que localizam a primeira ocorrência de uma cadeia de caracteres dentro de outra cadeia de StringComparison caracteres usando valores diferentes da enumeração.The following example demonstrates three overloads of the IndexOf method that find the first occurrence of a string within another string using different values of the StringComparison enumeration.

// This code example demonstrates the 
// System.String.IndexOf(String, ..., StringComparison) methods.

using System;
using System.Threading;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    string intro = "Find the first occurrence of a character using different " + 
                   "values of StringComparison.";
    string resultFmt = "Comparison: {0,-28} Location: {1,3}";

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
    string CapitalAWithRing = "\u00c5"; 

// Define a string to search. 
// The result of combining the characters LATIN SMALL LETTER A and COMBINING 
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
    string cat = "A Cheshire c" + "\u0061\u030a" + "t";

    int loc = 0;
    StringComparison[] scValues = {
        StringComparison.CurrentCulture,
        StringComparison.CurrentCultureIgnoreCase,
        StringComparison.InvariantCulture,
        StringComparison.InvariantCultureIgnoreCase,
        StringComparison.Ordinal,
        StringComparison.OrdinalIgnoreCase };

// Clear the screen and display an introduction.
    Console.Clear();
    Console.WriteLine(intro);

// Display the current culture because culture affects the result. For example, 
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    Console.WriteLine("The current culture is \"{0}\" - {1}.", 
                       Thread.CurrentThread.CurrentCulture.Name,
                       Thread.CurrentThread.CurrentCulture.DisplayName);

// Display the string to search for and the string to search.
    Console.WriteLine("Search for the string \"{0}\" in the string \"{1}\"", 
                       CapitalAWithRing, cat);
    Console.WriteLine();

// Note that in each of the following searches, we look for 
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
// the string was not found.
// Search using different values of StringComparison. Specify the start 
// index and count. 

    Console.WriteLine("Part 1: Start index and count are specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. Specify the 
// start index. 
    Console.WriteLine("\nPart 2: Start index is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. 
    Console.WriteLine("\nPart 3: Neither start index nor count is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }
    }
}

/*
Note: This code example was executed on a console whose user interface 
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*/
' This code example demonstrates the 
' System.String.IndexOf(String, ..., StringComparison) methods.

Imports System
Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Find the first occurrence of a character using different " & _
                              "values of StringComparison."
        Dim resultFmt As String = "Comparison: {0,-28} Location: {1,3}"
        
        ' Define a string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim CapitalAWithRing As String = "Å"
        
        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim cat As String = "A Cheshire c" & "å" & "t"
        
        Dim loc As Integer = 0
        Dim scValues As StringComparison() =  { _
                        StringComparison.CurrentCulture, _
                        StringComparison.CurrentCultureIgnoreCase, _
                        StringComparison.InvariantCulture, _
                        StringComparison.InvariantCultureIgnoreCase, _
                        StringComparison.Ordinal, _
                        StringComparison.OrdinalIgnoreCase }
        Dim sc As StringComparison
        
        ' Clear the screen and display an introduction.
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because culture affects the result. For example, 
        ' try this code example with the "sv-SE" (Swedish-Sweden) culture.
        Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
        Console.WriteLine("The current culture is ""{0}"" - {1}.", _
                           Thread.CurrentThread.CurrentCulture.Name, _ 
                           Thread.CurrentThread.CurrentCulture.DisplayName)
        
        ' Display the string to search for and the string to search.
        Console.WriteLine("Search for the string ""{0}"" in the string ""{1}""", _
                           CapitalAWithRing, cat)
        Console.WriteLine()
        
        ' Note that in each of the following searches, we look for 
        ' LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
        ' LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
        ' the string was not found.
        ' Search using different values of StringComparison. Specify the start 
        ' index and count.

        Console.WriteLine("Part 1: Start index and count are specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. Specify the 
        ' start index. 

        Console.WriteLine(vbCrLf & "Part 2: Start index is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. 

        Console.WriteLine(vbCrLf & "Part 3: Neither start index nor count is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
    
    End Sub 'Main
End Class 'Sample

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'This code example produces the following results:
'
'Find the first occurrence of a character using different values of StringComparison.
'The current culture is "en-US" - English (United States).
'Search for the string "Å" in the string "A Cheshire ca°t"
'
'Part 1: Start index and count are specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 2: Start index is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 3: Neither start index nor count is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'

Comentários

A numeração de índice começa em 0 (zero).Index numbering starts from 0 (zero). O parâmetro startIndex pode variar de 0 ao tamanho da instância da cadeia de caracteres.The startIndex parameter can range from 0 to the length of the string instance.

A pesquisa começa em startIndex e continua em startIndex + count -1.The search begins at startIndex and continues to startIndex + count -1. O caractere em startIndex + nãoestáincluído napesquisacount .The character at startIndex + count is not included in the search.

O parâmetro comparisonType especifica a procura do parâmetro value usando a cultura atual ou invariável, usando uma pesquisa com ou sem diferenciação de maiúsculas e minúsculas e usando regras de comparação de palavra ou ordinais.The comparisonType parameter specifies to search for the value parameter using the current or invariant culture, using a case-sensitive or case-insensitive search, and using word or ordinal comparison rules.

Notas aos Chamadores

Conjuntos de caracteres incluem caracteres ignoráveis, que são caracteres que não são considerados ao durante a realização de uma comparação linguística ou sensível à cultura.Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Em uma pesquisa sensível à cultura (ou seja, caso comparisonType não seja Ordinal ou OrdinalIgnoreCase), caso value contenha um caractere ignorável, o resultado é equivalente à pesquisa com esse caractere removido.In a culture-sensitive search (that is, if comparisonType is not Ordinal or OrdinalIgnoreCase), if value contains an ignorable character, the result is equivalent to searching with that character removed. Se value consistir apenas em um ou mais caracteres ignoráveis, IndexOf(String, Int32, Int32, StringComparison) o método sempre startIndexretornará, que é a posição do caractere na qual a pesquisa começa.If value consists only of one or more ignorable characters, the IndexOf(String, Int32, Int32, StringComparison) method always returns startIndex, which is the character position at which the search begins.

No exemplo a seguir, o IndexOf(String, Int32, Int32, StringComparison) método é usado para localizar a posição de um hífen flexível (U + 00AD) seguido por um "m" começando no terceiro até sexto posições de caractere em duas cadeias de caracteres.In the following example, the IndexOf(String, Int32, Int32, StringComparison) method is used to find the position of a soft hyphen (U+00AD) followed by an "m" starting in the third through sixth character positions in two strings. Apenas uma das cadeias de caracteres contém a subcadeia de caracteres necessária.Only one of the strings contains the required substring. Se o exemplo for executado no .NET Framework 4.NET Framework 4 ou posterior, em ambos os casos, como o hífen suave é um caractere ignorável, o método retornará o índice de "m" na cadeia de caracteres quando ele executar uma comparação sensível à cultura.If the example is run on the .NET Framework 4.NET Framework 4 or later, in both cases, because the soft hyphen is an ignorable character, the method returns the index of "m" in the string when it performs a culture-sensitive comparison. No entanto, quando ele executa uma comparação ordinal, ele encontra a subcadeia de caracteres somente na primeira cadeia de caracteres.When it performs an ordinal comparison, however, it finds the substring only in the first string. Observe que, no caso da primeira cadeia de caracteres, que inclui o hífen reversível seguido por um "m", o método não retorna o índice do hífen suave, mas, em vez disso, retorna o índice do "m" quando ele executa uma comparação sensível à cultura.Note that in the case of the first string, which includes the soft hyphen followed by an "m", the method fails to return the index of the soft hyphen but instead returns the index of the "m" when it performs a culture-sensitive comparison. O método só retorna o índice do hífen condicional na primeira cadeia de caracteres quando executa uma comparação ordinal.The method returns the index of the soft hyphen in the first string only when it performs an ordinal comparison.

[!code-csharpSystem.String.IndexOf#24] [!code-vbSystem.String.IndexOf#24][!code-csharpSystem.String.IndexOf#24] [!code-vbSystem.String.IndexOf#24]

IndexOf(String, Int32, StringComparison) IndexOf(String, Int32, StringComparison) IndexOf(String, Int32, StringComparison) IndexOf(String, Int32, StringComparison)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada no objeto String atual.Reports the zero-based index of the first occurrence of the specified string in the current String object. Os parâmetros especificam a posição de pesquisa inicial na cadeia de caracteres atual e o tipo de pesquisa a ser usado para a cadeia de caracteres especificada.Parameters specify the starting search position in the current string and the type of search to use for the specified string.

public:
 int IndexOf(System::String ^ value, int startIndex, StringComparison comparisonType);
public int IndexOf (string value, int startIndex, StringComparison comparisonType);
member this.IndexOf : string * int * StringComparison -> int
Public Function IndexOf (value As String, startIndex As Integer, comparisonType As StringComparison) As Integer

Parâmetros

value
String String String String

A cadeia de caracteres a ser buscada.The string to seek.

startIndex
Int32 Int32 Int32 Int32

A posição inicial da pesquisa.The search starting position.

comparisonType
StringComparison StringComparison StringComparison StringComparison

Um dos valores de enumeração que especifica as regras para a pesquisa.One of the enumeration values that specifies the rules for the search.

Retornos

A posição de índice baseado em zero do parâmetro value do início da instância atual se essa cadeia de caracteres for encontrada; caso contrário, -1.The zero-based index position of the value parameter from the start of the current instance if that string is found, or -1 if it is not. Se value for Empty, o valor retornado será startIndex.If value is Empty, the return value is startIndex.

Exceções

startIndex é menor que 0 (zero) ou maior que o tamanho dessa cadeia de caracteres.startIndex is less than 0 (zero) or greater than the length of this string.

comparisonType não é um valor StringComparison válido.comparisonType is not a valid StringComparison value.

Exemplos

O exemplo a seguir demonstra três sobrecargas do IndexOf método que localizam a primeira ocorrência de uma cadeia de caracteres dentro de outra cadeia de StringComparison caracteres usando valores diferentes da enumeração.The following example demonstrates three overloads of the IndexOf method that find the first occurrence of a string within another string using different values of the StringComparison enumeration.

// This code example demonstrates the 
// System.String.IndexOf(String, ..., StringComparison) methods.

using System;
using System.Threading;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    string intro = "Find the first occurrence of a character using different " + 
                   "values of StringComparison.";
    string resultFmt = "Comparison: {0,-28} Location: {1,3}";

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
    string CapitalAWithRing = "\u00c5"; 

// Define a string to search. 
// The result of combining the characters LATIN SMALL LETTER A and COMBINING 
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
    string cat = "A Cheshire c" + "\u0061\u030a" + "t";

    int loc = 0;
    StringComparison[] scValues = {
        StringComparison.CurrentCulture,
        StringComparison.CurrentCultureIgnoreCase,
        StringComparison.InvariantCulture,
        StringComparison.InvariantCultureIgnoreCase,
        StringComparison.Ordinal,
        StringComparison.OrdinalIgnoreCase };

// Clear the screen and display an introduction.
    Console.Clear();
    Console.WriteLine(intro);

// Display the current culture because culture affects the result. For example, 
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    Console.WriteLine("The current culture is \"{0}\" - {1}.", 
                       Thread.CurrentThread.CurrentCulture.Name,
                       Thread.CurrentThread.CurrentCulture.DisplayName);

// Display the string to search for and the string to search.
    Console.WriteLine("Search for the string \"{0}\" in the string \"{1}\"", 
                       CapitalAWithRing, cat);
    Console.WriteLine();

// Note that in each of the following searches, we look for 
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
// the string was not found.
// Search using different values of StringComparison. Specify the start 
// index and count. 

    Console.WriteLine("Part 1: Start index and count are specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. Specify the 
// start index. 
    Console.WriteLine("\nPart 2: Start index is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. 
    Console.WriteLine("\nPart 3: Neither start index nor count is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }
    }
}

/*
Note: This code example was executed on a console whose user interface 
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*/
' This code example demonstrates the 
' System.String.IndexOf(String, ..., StringComparison) methods.

Imports System
Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Find the first occurrence of a character using different " & _
                              "values of StringComparison."
        Dim resultFmt As String = "Comparison: {0,-28} Location: {1,3}"
        
        ' Define a string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim CapitalAWithRing As String = "Å"
        
        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim cat As String = "A Cheshire c" & "å" & "t"
        
        Dim loc As Integer = 0
        Dim scValues As StringComparison() =  { _
                        StringComparison.CurrentCulture, _
                        StringComparison.CurrentCultureIgnoreCase, _
                        StringComparison.InvariantCulture, _
                        StringComparison.InvariantCultureIgnoreCase, _
                        StringComparison.Ordinal, _
                        StringComparison.OrdinalIgnoreCase }
        Dim sc As StringComparison
        
        ' Clear the screen and display an introduction.
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because culture affects the result. For example, 
        ' try this code example with the "sv-SE" (Swedish-Sweden) culture.
        Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
        Console.WriteLine("The current culture is ""{0}"" - {1}.", _
                           Thread.CurrentThread.CurrentCulture.Name, _ 
                           Thread.CurrentThread.CurrentCulture.DisplayName)
        
        ' Display the string to search for and the string to search.
        Console.WriteLine("Search for the string ""{0}"" in the string ""{1}""", _
                           CapitalAWithRing, cat)
        Console.WriteLine()
        
        ' Note that in each of the following searches, we look for 
        ' LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
        ' LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
        ' the string was not found.
        ' Search using different values of StringComparison. Specify the start 
        ' index and count.

        Console.WriteLine("Part 1: Start index and count are specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. Specify the 
        ' start index. 

        Console.WriteLine(vbCrLf & "Part 2: Start index is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. 

        Console.WriteLine(vbCrLf & "Part 3: Neither start index nor count is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
    
    End Sub 'Main
End Class 'Sample

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'This code example produces the following results:
'
'Find the first occurrence of a character using different values of StringComparison.
'The current culture is "en-US" - English (United States).
'Search for the string "Å" in the string "A Cheshire ca°t"
'
'Part 1: Start index and count are specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 2: Start index is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 3: Neither start index nor count is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'

Comentários

A numeração de índice começa em 0.Index numbering starts from 0. O parâmetro startIndex pode variar de 0 ao tamanho da instância da cadeia de caracteres.The startIndex parameter can range from 0 to the length of the string instance. Se startIndex for igual ao comprimento da instância de cadeia de caracteres, o método retornará-1.If startIndex equals the length of the string instance, the method returns -1.

O parâmetro comparisonType especifica a procura do parâmetro value usando a cultura atual ou invariável, usando uma pesquisa com ou sem diferenciação de maiúsculas e minúsculas e usando regras de comparação de palavra ou ordinais.The comparisonType parameter specifies to search for the value parameter using the current or invariant culture, using a case-sensitive or case-insensitive search, and using word or ordinal comparison rules.

Notas aos Chamadores

Conjuntos de caracteres incluem caracteres ignoráveis, que são caracteres que não são considerados ao durante a realização de uma comparação linguística ou sensível à cultura.Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Em uma pesquisa sensível à cultura (ou seja, caso comparisonType não seja Ordinal ou OrdinalIgnoreCase), caso value contenha um caractere ignorável, o resultado é equivalente à pesquisa com esse caractere removido.In a culture-sensitive search (that is, if comparisonType is not Ordinal or OrdinalIgnoreCase), if value contains an ignorable character, the result is equivalent to searching with that character removed. Se value consistir apenas em um ou mais caracteres ignoráveis, IndexOf(String, Int32, StringComparison) o método sempre startIndexretornará, que é a posição do caractere na qual a pesquisa começa.If value consists only of one or more ignorable characters, the IndexOf(String, Int32, StringComparison) method always returns startIndex, which is the character position at which the search begins.

No exemplo a seguir, o IndexOf(String, Int32, StringComparison) método é usado para localizar a posição de um hífen flexível (U + 00AD) seguido por um "m" começando com a terceira posição de caractere em duas cadeias de caracteres.In the following example, the IndexOf(String, Int32, StringComparison) method is used to find the position of a soft hyphen (U+00AD) followed by an "m" starting with the third character position in two strings. Somente uma das cadeias de caracteres contém a subcadeia necessária. Se o exemplo for executado no .NET Framework 4.NET Framework 4 ou posterior, em ambos os casos, como o hífen suave é um caractere ignorável, o método retornará o índice de "m" na cadeia de caracteres quando ele executar uma comparação sensível à cultura.Only one of the strings contains the required substring.If the example is run on the .NET Framework 4.NET Framework 4 or later, in both cases, because the soft hyphen is an ignorable character, the method returns the index of "m" in the string when it performs a culture-sensitive comparison. No caso da primeira cadeia de caracteres, que inclui o hífen condicional seguido de um "m", o método não retorna o índice do hífen virtual, mas retorna o índice do "m".Note that in the case of the first string, which includes the soft hyphen followed by an "m", the method fails to return the index of the soft hyphen but instead returns the index of the "m". O método só retorna o índice do hífen condicional na primeira cadeia de caracteres quando executa uma comparação ordinal.The method returns the index of the soft hyphen in the first string only when it performs an ordinal comparison.

[!code-csharpSystem.String.IndexOf#25] [!code-vbSystem.String.IndexOf#25][!code-csharpSystem.String.IndexOf#25] [!code-vbSystem.String.IndexOf#25]

IndexOf(Char, Int32, Int32) IndexOf(Char, Int32, Int32) IndexOf(Char, Int32, Int32) IndexOf(Char, Int32, Int32)

Relata o índice baseado em zero da primeira ocorrência do caractere especificado nessa instância.Reports the zero-based index of the first occurrence of the specified character in this instance. A pesquisa é iniciada em uma posição de caractere especificada e examina um número especificado de posições de caracteres.The search starts at a specified character position and examines a specified number of character positions.

public:
 int IndexOf(char value, int startIndex, int count);
public int IndexOf (char value, int startIndex, int count);
member this.IndexOf : char * int * int -> int
Public Function IndexOf (value As Char, startIndex As Integer, count As Integer) As Integer

Parâmetros

value
Char Char Char Char

Um caractere Unicode a ser buscado.A Unicode character to seek.

startIndex
Int32 Int32 Int32 Int32

A posição inicial da pesquisa.The search starting position.

count
Int32 Int32 Int32 Int32

O número de posições de caractere a serem examinadas.The number of character positions to examine.

Retornos

A posição de índice baseado em zero de value do início da cadeia de caracteres se esse caractere for encontrado ou -1 se não for.The zero-based index position of value from the start of the string if that character is found, or -1 if it is not.

Exceções

count ou startIndex é negativo.count or startIndex is negative.

- ou --or- startIndex é maior que o tamanho da cadeia de caracteres.startIndex is greater than the length of this string.

- ou --or- count é maior que o tamanho da cadeia de caracteres menos startIndex.count is greater than the length of this string minus startIndex.

Exemplos

O exemplo a seguir demonstra IndexOf o método.The following example demonstrates the IndexOf method.

// Example for the String::IndexOf( Char, int, int ) method.
using namespace System;
void FindAllChar( Char target, String^ searched )
{
   Console::Write( "The character '{0}' occurs at position(s): ", target );
   int startIndex = -1;
   int hitCount = 0;
   
   // Search for all occurrences of the target.
   while ( true )
   {
      startIndex = searched->IndexOf( target, startIndex + 1, searched->Length - startIndex - 1 );
      
      // Exit the loop if the target is not found.
      if ( startIndex < 0 )
            break;

      Console::Write( "{0}, ", startIndex );
      hitCount++;
   }

   Console::WriteLine( "occurrences: {0}", hitCount );
}

int main()
{
   String^ br1 = "0----+----1----+----2----+----3----+----"
   "4----+----5----+----6----+----7";
   String^ br2 = "0123456789012345678901234567890123456789"
   "0123456789012345678901234567890";
   String^ str = "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi "
   "ABCDEFGHI abcdefghi ABCDEFGHI";
   Console::WriteLine( "This example of String::IndexOf( Char, int, int )\n"
   "generates the following output." );
   Console::WriteLine( "{0}{1}{0}{2}{0}{3}{0}", Environment::NewLine, br1, br2, str );
   FindAllChar( 'A', str );
   FindAllChar( 'a', str );
   FindAllChar( 'I', str );
   FindAllChar( 'i', str );
   FindAllChar( '@', str );
   FindAllChar( ' ', str );
}

/*
This example of String::IndexOf( Char, int, int )
generates the following output.

0----+----1----+----2----+----3----+----4----+----5----+----6----+----7
01234567890123456789012345678901234567890123456789012345678901234567890
ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI

The character 'A' occurs at position(s): 0, 20, 40, 60, occurrences: 4
The character 'a' occurs at position(s): 10, 30, 50, occurrences: 3
The character 'I' occurs at position(s): 8, 28, 48, 68, occurrences: 4
The character 'i' occurs at position(s): 18, 38, 58, occurrences: 3
The character '@' occurs at position(s): occurrences: 0
The character ' ' occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6
*/
// Example for the String.IndexOf( char, int, int ) method.
using System;

class IndexOfCII 
{
    public static void Main() 
    {
        string br1 = 
            "0----+----1----+----2----+----3----+----" +
            "4----+----5----+----6----+----7";
        string br2 = 
            "0123456789012345678901234567890123456789" +
            "0123456789012345678901234567890";
        string str = 
            "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi " +
            "ABCDEFGHI abcdefghi ABCDEFGHI";

        Console.WriteLine( 
            "This example of String.IndexOf( char, int, int )\n" +
            "generates the following output." );
        Console.WriteLine( 
            "{0}{1}{0}{2}{0}{3}{0}", 
            Environment.NewLine, br1, br2, str );

        FindAllChar( 'A', str );
        FindAllChar( 'a', str );
        FindAllChar( 'I', str );
        FindAllChar( 'i', str );
        FindAllChar( '@', str );
        FindAllChar( ' ', str );
    }

    static void FindAllChar( Char target, String searched )
    {
        Console.Write( 
            "The character '{0}' occurs at position(s): ", 
            target );

        int     startIndex = -1;
        int     hitCount = 0;

        // Search for all occurrences of the target.
        while( true )
        {
            startIndex = searched.IndexOf( 
                target, startIndex + 1, 
                searched.Length - startIndex - 1 );

            // Exit the loop if the target is not found.
            if( startIndex < 0 )
                break;

            Console.Write( "{0}, ", startIndex );
            hitCount++;
        }

        Console.WriteLine( "occurrences: {0}", hitCount );
    }
}

/*
This example of String.IndexOf( char, int, int )
generates the following output.

0----+----1----+----2----+----3----+----4----+----5----+----6----+----7
01234567890123456789012345678901234567890123456789012345678901234567890
ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI

The character 'A' occurs at position(s): 0, 20, 40, 60, occurrences: 4
The character 'a' occurs at position(s): 10, 30, 50, occurrences: 3
The character 'I' occurs at position(s): 8, 28, 48, 68, occurrences: 4
The character 'i' occurs at position(s): 18, 38, 58, occurrences: 3
The character '@' occurs at position(s): occurrences: 0
The character ' ' occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6
*/
' Example for the String.IndexOf( Char, Integer, Integer ) method.
Imports System
Imports Microsoft.VisualBasic

Module IndexOfCII
   
    Sub Main()
        Dim br1 As String = _
            "0----+----1----+----2----+----3----+----" & _
            "4----+----5----+----6----+----7"
        Dim br2 As String = _
            "0123456789012345678901234567890123456789" & _
            "0123456789012345678901234567890"
        Dim str As String = _
            "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi " & _
            "ABCDEFGHI abcdefghi ABCDEFGHI"
          
        Console.WriteLine( _
            "This example of String.IndexOf( Char, Integer, Integer )" & _
            vbCrLf & "generates the following output." )
        Console.WriteLine( _
            "{0}{1}{0}{2}{0}{3}{0}", _
            Environment.NewLine, br1, br2, str)

        FindAllChar("A"c, str)
        FindAllChar("a"c, str)
        FindAllChar("I"c, str)
        FindAllChar("i"c, str)
        FindAllChar("@"c, str)
        FindAllChar(" "c, str)
    End Sub 'Main
       
    Sub FindAllChar(target As Char, searched As String)

        Console.Write( _
            "The character ""{0}"" occurs at position(s): ", target)
          
        Dim startIndex As Integer = - 1
        Dim hitCount As Integer = 0
          
        ' Search for all occurrences of the target.
        While True
            startIndex = searched.IndexOf( _
                target, startIndex + 1, _
                searched.Length - startIndex - 1)

            ' Exit the loop if the target is not found.
            If startIndex < 0 Then
                Exit While
            End If 

            Console.Write("{0}, ", startIndex)
            hitCount += 1
        End While
          
        Console.WriteLine("occurrences: {0}", hitCount)

    End Sub 'FindAllChar
End Module 'IndexOfCII

' This example of String.IndexOf( Char, Integer, Integer )
' generates the following output.
' 
' 0----+----1----+----2----+----3----+----4----+----5----+----6----+----7
' 01234567890123456789012345678901234567890123456789012345678901234567890
' ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI
' 
' The character "A" occurs at position(s): 0, 20, 40, 60, occurrences: 4
' The character "a" occurs at position(s): 10, 30, 50, occurrences: 3
' The character "I" occurs at position(s): 8, 28, 48, 68, occurrences: 4
' The character "i" occurs at position(s): 18, 38, 58, occurrences: 3
' The character "@" occurs at position(s): occurrences: 0
' The character " " occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6

Comentários

A pesquisa começa em startIndex e continua em startIndex + count -1.The search begins at startIndex and continues to startIndex + count -1. O caractere em startIndex + nãoestáincluído napesquisacount .The character at startIndex + count is not included in the search.

A numeração de índice começa em 0 (zero).Index numbering starts from 0 (zero). O parâmetro startIndex pode variar de 0 ao tamanho da instância da cadeia de caracteres.The startIndex parameter can range from 0 to the length of the string instance.

Este método executa uma pesquisa ordinal (insensível à cultura), onde um caractere só é considerado equivalente a um outro caractere caso os valores escalares Unicode sejam os mesmos.This method performs an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if their Unicode scalar values are the same. Para executar uma pesquisa sensível à cultura, use o método CompareInfo.IndexOf, em que um valor escalar Unicode representando um caractere pré-composto como a ligadura "Æ" (U+00C6) pode ser considerado equivalente a qualquer ocorrência dos componentes do caractere na sequência correta, como "AE" (U+0041, U+0045), dependendo da cultura.To perform a culture-sensitive search, use the CompareInfo.IndexOf method, where a Unicode scalar value representing a precomposed character, such as the ligature "Æ" (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture.

Veja também

IndexOf(String, StringComparison) IndexOf(String, StringComparison) IndexOf(String, StringComparison) IndexOf(String, StringComparison)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada no objeto String atual.Reports the zero-based index of the first occurrence of the specified string in the current String object. Um parâmetro especifica o tipo de pesquisa a ser usado para a cadeia de caracteres especificada.A parameter specifies the type of search to use for the specified string.

public:
 int IndexOf(System::String ^ value, StringComparison comparisonType);
public int IndexOf (string value, StringComparison comparisonType);
member this.IndexOf : string * StringComparison -> int
Public Function IndexOf (value As String, comparisonType As StringComparison) As Integer

Parâmetros

value
String String String String

A cadeia de caracteres a ser buscada.The string to seek.

comparisonType
StringComparison StringComparison StringComparison StringComparison

Um dos valores de enumeração que especifica as regras para a pesquisa.One of the enumeration values that specifies the rules for the search.

Retornos

A posição do índice do parâmetro value caso essa cadeia de caracteres seja encontrada, ou -1 caso não seja.The index position of the value parameter if that string is found, or -1 if it is not. Se value for Empty, o valor retornado será 0.If value is Empty, the return value is 0.

Exceções

comparisonType não é um valor StringComparison válido.comparisonType is not a valid StringComparison value.

Exemplos

O exemplo a seguir demonstra três sobrecargas do IndexOf método que localizam a primeira ocorrência de uma cadeia de caracteres dentro de outra cadeia de StringComparison caracteres usando valores diferentes da enumeração.The following example demonstrates three overloads of the IndexOf method that find the first occurrence of a string within another string using different values of the StringComparison enumeration.

// This code example demonstrates the 
// System.String.IndexOf(String, ..., StringComparison) methods.

using System;
using System.Threading;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    string intro = "Find the first occurrence of a character using different " + 
                   "values of StringComparison.";
    string resultFmt = "Comparison: {0,-28} Location: {1,3}";

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
    string CapitalAWithRing = "\u00c5"; 

// Define a string to search. 
// The result of combining the characters LATIN SMALL LETTER A and COMBINING 
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
    string cat = "A Cheshire c" + "\u0061\u030a" + "t";

    int loc = 0;
    StringComparison[] scValues = {
        StringComparison.CurrentCulture,
        StringComparison.CurrentCultureIgnoreCase,
        StringComparison.InvariantCulture,
        StringComparison.InvariantCultureIgnoreCase,
        StringComparison.Ordinal,
        StringComparison.OrdinalIgnoreCase };

// Clear the screen and display an introduction.
    Console.Clear();
    Console.WriteLine(intro);

// Display the current culture because culture affects the result. For example, 
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    Console.WriteLine("The current culture is \"{0}\" - {1}.", 
                       Thread.CurrentThread.CurrentCulture.Name,
                       Thread.CurrentThread.CurrentCulture.DisplayName);

// Display the string to search for and the string to search.
    Console.WriteLine("Search for the string \"{0}\" in the string \"{1}\"", 
                       CapitalAWithRing, cat);
    Console.WriteLine();

// Note that in each of the following searches, we look for 
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
// the string was not found.
// Search using different values of StringComparison. Specify the start 
// index and count. 

    Console.WriteLine("Part 1: Start index and count are specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. Specify the 
// start index. 
    Console.WriteLine("\nPart 2: Start index is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. 
    Console.WriteLine("\nPart 3: Neither start index nor count is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }
    }
}

/*
Note: This code example was executed on a console whose user interface 
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*/
' This code example demonstrates the 
' System.String.IndexOf(String, ..., StringComparison) methods.

Imports System
Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Find the first occurrence of a character using different " & _
                              "values of StringComparison."
        Dim resultFmt As String = "Comparison: {0,-28} Location: {1,3}"
        
        ' Define a string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim CapitalAWithRing As String = "Å"
        
        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim cat As String = "A Cheshire c" & "å" & "t"
        
        Dim loc As Integer = 0
        Dim scValues As StringComparison() =  { _
                        StringComparison.CurrentCulture, _
                        StringComparison.CurrentCultureIgnoreCase, _
                        StringComparison.InvariantCulture, _
                        StringComparison.InvariantCultureIgnoreCase, _
                        StringComparison.Ordinal, _
                        StringComparison.OrdinalIgnoreCase }
        Dim sc As StringComparison
        
        ' Clear the screen and display an introduction.
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because culture affects the result. For example, 
        ' try this code example with the "sv-SE" (Swedish-Sweden) culture.
        Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
        Console.WriteLine("The current culture is ""{0}"" - {1}.", _
                           Thread.CurrentThread.CurrentCulture.Name, _ 
                           Thread.CurrentThread.CurrentCulture.DisplayName)
        
        ' Display the string to search for and the string to search.
        Console.WriteLine("Search for the string ""{0}"" in the string ""{1}""", _
                           CapitalAWithRing, cat)
        Console.WriteLine()
        
        ' Note that in each of the following searches, we look for 
        ' LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
        ' LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
        ' the string was not found.
        ' Search using different values of StringComparison. Specify the start 
        ' index and count.

        Console.WriteLine("Part 1: Start index and count are specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. Specify the 
        ' start index. 

        Console.WriteLine(vbCrLf & "Part 2: Start index is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. 

        Console.WriteLine(vbCrLf & "Part 3: Neither start index nor count is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
    
    End Sub 'Main
End Class 'Sample

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'This code example produces the following results:
'
'Find the first occurrence of a character using different values of StringComparison.
'The current culture is "en-US" - English (United States).
'Search for the string "Å" in the string "A Cheshire ca°t"
'
'Part 1: Start index and count are specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 2: Start index is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 3: Neither start index nor count is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'

Comentários

A numeração de índice começa do zero.Index numbering starts from zero.

O parâmetro comparisonType especifica a procura do parâmetro value usando a cultura atual ou invariável, usando uma pesquisa com ou sem diferenciação de maiúsculas e minúsculas e usando regras de comparação de palavra ou ordinais.The comparisonType parameter specifies to search for the value parameter using the current or invariant culture, using a case-sensitive or case-insensitive search, and using word or ordinal comparison rules.

Notas aos Chamadores

Conjuntos de caracteres incluem caracteres ignoráveis, que são caracteres que não são considerados ao durante a realização de uma comparação linguística ou sensível à cultura.Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Em uma pesquisa sensível à cultura (ou seja, caso comparisonType não seja Ordinal ou OrdinalIgnoreCase), caso value contenha um caractere ignorável, o resultado é equivalente à pesquisa com esse caractere removido.In a culture-sensitive search (that is, if comparisonType is not Ordinal or OrdinalIgnoreCase), if value contains an ignorable character, the result is equivalent to searching with that character removed. Se value consistir apenas em um ou mais caracteres ignoráveis, IndexOf(String, StringComparison) o método sempre retorna 0 (zero) para indicar que a correspondência é encontrada no início da instância atual.If value consists only of one or more ignorable characters, the IndexOf(String, StringComparison) method always returns 0 (zero) to indicate that the match is found at the beginning of the current instance.

No exemplo a seguir, o IndexOf(String, StringComparison) método é usado para encontrar três subcadeias de caracteres (um hífen simples (U + 00AD), um hífen reversível seguido por "n" e um hífen, seguido por "m") em duas cadeias de caracteres.In the following example, the IndexOf(String, StringComparison) method is used to find three substrings (a soft hyphen (U+00AD), a soft hyphen followed by "n", and a soft hyphen followed by "m") in two strings. Apenas uma das cadeias de caracteres contém um hífen condicional.Only one of the strings contains a soft hyphen. Se o exemplo for executado no .NET Framework 4.NET Framework 4 ou posterior, como o hífen suave é um caractere ignorável, uma pesquisa sensível à cultura retorna o mesmo valor que ele retornaria se o hífen flexível não estivesse incluído na cadeia de caracteres de pesquisa.If the example is run on the .NET Framework 4.NET Framework 4 or later, because the soft hyphen is an ignorable character, a culture-sensitive search returns the same value that it would return if the soft hyphen were not included in the search string. No entanto, uma pesquisa ordinal localiza com êxito o hífen suave em uma cadeia de caracteres e relata que ela está ausente da segunda cadeia de caracteres.An ordinal search, however, successfully finds the soft hyphen in one string and reports that it is absent from the second string.

[!code-csharpSystem.String.IndexOf#26] [!code-vbSystem.String.IndexOf#26][!code-csharpSystem.String.IndexOf#26] [!code-vbSystem.String.IndexOf#26]

IndexOf(Char, StringComparison) IndexOf(Char, StringComparison) IndexOf(Char, StringComparison) IndexOf(Char, StringComparison)

Relata o índice baseado em zero da primeira ocorrência do caractere Unicode especificado na cadeia de caracteres.Reports the zero-based index of the first occurrence of the specified Unicode character in this string. Um parâmetro especifica o tipo de pesquisa a ser usado para o caractere especificado.A parameter specifies the type of search to use for the specified character.

public:
 int IndexOf(char value, StringComparison comparisonType);
public int IndexOf (char value, StringComparison comparisonType);
member this.IndexOf : char * StringComparison -> int
Public Function IndexOf (value As Char, comparisonType As StringComparison) As Integer

Parâmetros

value
Char Char Char Char

O caractere a buscar.The character to seek.

comparisonType
StringComparison StringComparison StringComparison StringComparison

Um valor de enumeração que especifica as regras para a pesquisa.An enumeration value that specifies the rules for the search.

Retornos

O índice com base em zero de value caso o caractere seja encontrado -1 caso não seja.The zero-based index of value if that character is found, or -1 if it is not.

Exceções

comparisonType não é um valor StringComparison válido.comparisonType is not a valid StringComparison value.

Comentários

A numeração de índice começa do zero.Index numbering starts from zero.

O comparisonType parâmetro é um StringComparison membro de enumeração que especifica value se a pesquisa do argumento usa a cultura atual ou invariável, diferencia maiúsculas de minúsculas ou não faz distinção de maiúsculas e minúsculas ou usa regras de comparação de palavras ou ordinais.The comparisonType parameter is a StringComparison enumeration member that specifies whether the search for the value argument uses the current or invariant culture, is case-sensitive or case-insensitive, or uses word or ordinal comparison rules.

IndexOf(Char, Int32) IndexOf(Char, Int32) IndexOf(Char, Int32) IndexOf(Char, Int32)

Relata o índice baseado em zero da primeira ocorrência do caractere Unicode especificado na cadeia de caracteres.Reports the zero-based index of the first occurrence of the specified Unicode character in this string. A pesquisa é iniciada em uma posição de caractere especificada.The search starts at a specified character position.

public:
 int IndexOf(char value, int startIndex);
public int IndexOf (char value, int startIndex);
member this.IndexOf : char * int -> int
Public Function IndexOf (value As Char, startIndex As Integer) As Integer

Parâmetros

value
Char Char Char Char

Um caractere Unicode a ser buscado.A Unicode character to seek.

startIndex
Int32 Int32 Int32 Int32

A posição inicial da pesquisa.The search starting position.

Retornos

A posição de índice baseado em zero de value do início da cadeia de caracteres se esse caractere for encontrado ou -1 se não for.The zero-based index position of value from the start of the string if that character is found, or -1 if it is not.

Exceções

startIndex é menor que 0 (zero) ou maior que o tamanho da cadeia de caracteres.startIndex is less than 0 (zero) or greater than the length of the string.

Exemplos

O exemplo a seguir demonstra IndexOf o método.The following example demonstrates the IndexOf method.

// Sample for String::IndexOf(Char, Int32)
using namespace System;
int main()
{
   String^ br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-";
   String^ br2 = "0123456789012345678901234567890123456789012345678901234567890123456";
   String^ str = "Now is the time for all good men to come to the aid of their party.";
   int start;
   int at;
   Console::WriteLine();
   Console::WriteLine( "All occurrences of 't' from position 0 to {0}.", str->Length - 1 );
   Console::WriteLine( "{1}{0}{2}{0}{3}{0}", Environment::NewLine, br1, br2, str );
   Console::Write( "The letter 't' occurs at position(s): " );
   at = 0;
   start = 0;
   while ( (start < str->Length) && (at > -1) )
   {
      at = str->IndexOf( 't', start );
      if ( at == -1 )
            break;

      Console::Write( "{0} ", at );
      start = at + 1;
   }

   Console::WriteLine();
}

/*
This example produces the following results:

All occurrences of 't' from position 0 to 66.
0----+----1----+----2----+----3----+----4----+----5----+----6----+-
0123456789012345678901234567890123456789012345678901234567890123456
Now is the time for all good men to come to the aid of their party.

The letter 't' occurs at position(s): 7 11 33 41 44 55 64

*/
string br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+---";
string br2 = "012345678901234567890123456789012345678901234567890123456789012345678";
string str = "Now is the time for all good men to come to the aid of their country.";
int start;
int at;

Console.WriteLine();
Console.WriteLine("All occurrences of 't' from position 0 to {0}.", str.Length-1);
Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str);
Console.Write("The letter 't' occurs at position(s): ");

at = 0;
start = 0; 
while((start < str.Length) && (at > -1))
{
    at = str.IndexOf('t', start);
    if (at == -1) break;
    Console.Write("{0} ", at);
    start = at+1;
}
Console.WriteLine();

/*
This example produces the following results:

All occurrences of 't' from position 0 to 68.
0----+----1----+----2----+----3----+----4----+----5----+----6----+---
012345678901234567890123456789012345678901234567890123456789012345678
Now is the time for all good men to come to the aid of their country.

The letter 't' occurs at position(s): 7 11 33 41 44 55 65

*/
' Sample for String.IndexOf(Char, Int32)

Module Sample
    Sub Main()

        Dim br1 As String = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-"
        Dim br2 As String = "0123456789012345678901234567890123456789012345678901234567890123456"
        Dim str As String = "Now is the time for all good men to come to the aid of their party."
        Dim start As Integer
        Dim at As Integer

        Console.WriteLine()
        Console.WriteLine("All occurrences of 't' from position 0 to {0}.", str.Length - 1)
        Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str)
        Console.Write("The letter 't' occurs at position(s): ")

        at = 0
        start = 0
        While start < str.Length AndAlso at > -1
            at = str.IndexOf("t"c, start)
            If at = -1 Then
                Exit While
            End If
            Console.Write("{0} ", at)
            start = at + 1
        End While
        Console.WriteLine()
    End Sub
End Module
'
'This example produces the following results:
'
'All occurrences of 't' from position 0 to 66.
'0----+----1----+----2----+----3----+----4----+----5----+----6----+-
'0123456789012345678901234567890123456789012345678901234567890123456
'Now is the time for all good men to come to the aid of their party.
'
'The letter 't' occurs at position(s): 7 11 33 41 44 55 64
'
'

Comentários

A numeração de índice começa em 0.Index numbering starts from 0. O parâmetro startIndex pode variar de 0 ao tamanho da instância da cadeia de caracteres.The startIndex parameter can range from 0 to the length of the string instance. Se startIndex for igual ao comprimento da instância de cadeia de caracteres, o método retornará-1.If startIndex equals the length of the string instance, the method returns -1.

A pesquisa vai de startIndex até o final da cadeia de caracteres.The search ranges from startIndex to the end of the string.

Este método executa uma pesquisa ordinal (insensível à cultura), onde um caractere só é considerado equivalente a um outro caractere caso os valores escalares Unicode sejam os mesmos.This method performs an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if their Unicode scalar values are the same. Para executar uma pesquisa sensível à cultura, use o método CompareInfo.IndexOf, em que um valor escalar Unicode representando um caractere pré-composto como a ligadura "Æ" (U+00C6) pode ser considerado equivalente a qualquer ocorrência dos componentes do caractere na sequência correta, como "AE" (U+0041, U+0045), dependendo da cultura.To perform a culture-sensitive search, use the CompareInfo.IndexOf method, where a Unicode scalar value representing a precomposed character, such as the ligature "Æ" (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture.

Veja também

IndexOf(String) IndexOf(String) IndexOf(String) IndexOf(String)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada nessa instância.Reports the zero-based index of the first occurrence of the specified string in this instance.

public:
 int IndexOf(System::String ^ value);
public int IndexOf (string value);
member this.IndexOf : string -> int
Public Function IndexOf (value As String) As Integer

Parâmetros

value
String String String String

A cadeia de caracteres a ser buscada.The string to seek.

Retornos

A posição do índice com base em zero de value caso essa cadeia de caracteres seja encontrada ou -1 caso não seja.The zero-based index position of value if that string is found, or -1 if it is not. Se value for Empty, o valor retornado será 0.If value is Empty, the return value is 0.

Exceções

Exemplos

O exemplo a seguir pesquisa o "n" em "animal".The following example searches for the "n" in "animal". Como os índices de cadeia de caracteres começam em zero em IndexOf(String) vez de um, o método indica que "n" está na posição 1.Because string indexes begin at zero rather than one, the IndexOf(String) method indicates that the "n" is at position 1.

using namespace System;

void main()
{
   String^ str = "animal";
   String^ toFind = "n";
   int index = str->IndexOf("n");
   Console::WriteLine("Found '{0}' in '{1}' at position {2}",
                        toFind, str, index);

}
// The example displays the following output:
//        Found 'n' in 'animal' at position 1
String str = "animal";
String toFind = "n";
int index = str.IndexOf("n");
Console.WriteLine("Found '{0}' in '{1}' at position {2}",
                toFind, str, index);

// The example displays the following output:
//        Found 'n' in 'animal' at position 1
Public Module Example
   Public Sub Main()
      Dim str As String = "animal"
      Dim toFind As String = "n"
      Dim index As Integer = str.IndexOf("n")
      Console.WriteLine("Found '{0}' in '{1}' at position {2}",
                        toFind, str, index)
   End Sub
End Module
' The example displays the following output:
'       Found 'n' in 'animal' at position 1

O exemplo a seguir usa IndexOf o método para determinar a posição inicial de um nome de animal em uma sentença.The following example uses the IndexOf method to determine the starting position of an animal name in a sentence. Em seguida, ele usa essa posição para inserir um adjetivo que descreve o animal na sentença.It then uses this position to insert an adjective that describes the animal into the sentence.

using namespace System;

int main()
{
   String^ animal1 = "fox";
   String^ animal2 = "dog";
   String^ strTarget = String::Format( "The {0} jumps over the {1}.", animal1, animal2 );
   Console::WriteLine( "The original string is:{0}{1}{0}", Environment::NewLine, strTarget );
   Console::Write( "Enter an adjective (or group of adjectives) to describe the {0}: ==> ", animal1 );
   String^ adj1 = Console::ReadLine();
   Console::Write( "Enter an adjective (or group of adjectives) to describe the {0}: ==> ", animal2 );
   String^ adj2 = Console::ReadLine();
   adj1 = String::Concat( adj1->Trim(), " " );
   adj2 = String::Concat( adj2->Trim(), " " );
   strTarget = strTarget->Insert( strTarget->IndexOf( animal1 ), adj1 );
   strTarget = strTarget->Insert( strTarget->IndexOf( animal2 ), adj2 );
   Console::WriteLine( " {0}The final string is: {0} {1}", Environment::NewLine, strTarget );
}
// Output from the example might appear as follows:
//       The original string is:
//       The fox jumps over the dog.
//       
//       Enter an adjective (or group of adjectives) to describe the fox: ==> bold
//       Enter an adjective (or group of adjectives) to describe the dog: ==> lazy
//       
//       The final string is:
//       The bold fox jumps over the lazy dog.
using System;

public class Example {
    public static void Main() 
    {
        string animal1 = "fox";
        string animal2 = "dog";

        string strTarget = String.Format("The {0} jumps over the {1}.", 
                                         animal1, animal2);

        Console.WriteLine("The original string is:{0}{1}{0}", 
                          Environment.NewLine, strTarget);

        Console.Write("Enter an adjective (or group of adjectives) " +
                      "to describe the {0}: ==> ", animal1);
        string adj1 = Console.ReadLine();

        Console.Write("Enter an adjective (or group of adjectives) " + 
                      "to describe the {0}: ==> ", animal2);    
        string adj2 = Console.ReadLine();

        adj1 = adj1.Trim() + " ";
        adj2 = adj2.Trim() + " ";

        strTarget = strTarget.Insert(strTarget.IndexOf(animal1), adj1);
        strTarget = strTarget.Insert(strTarget.IndexOf(animal2), adj2);

        Console.WriteLine("{0}The final string is:{0}{1}", 
                          Environment.NewLine, strTarget);
    }
}
// Output from the example might appear as follows:
//       The original string is:
//       The fox jumps over the dog.
//       
//       Enter an adjective (or group of adjectives) to describe the fox: ==> bold
//       Enter an adjective (or group of adjectives) to describe the dog: ==> lazy
//       
//       The final string is:
//       The bold fox jumps over the lazy dog.
Public Class Example
    Public Shared Sub Main()
        Dim animal1 As String = "fox"
        Dim animal2 As String = "dog"
        Dim strTarget As String = String.Format("The {0} jumps over the {1}.", 
                                                animal1, animal2)
        
        Console.WriteLine("The original string is: {0}{1}{0}", 
                          Environment.NewLine, strTarget)
        
        Console.Write("Enter an adjective (or group of adjectives) " +
                      "to describe the {0}: ==> ", animal1)
        Dim adj1 As String = Console.ReadLine()
        
        Console.Write("Enter an adjective (or group of adjectives) " + 
                      "to describe the {0}: ==> ", animal2)
        Dim adj2 As String = Console.ReadLine()
        
        adj1 = adj1.Trim() + " "
        adj2 = adj2.Trim() + " "
        
        strTarget = strTarget.Insert(strTarget.IndexOf(animal1), adj1)
        strTarget = strTarget.Insert(strTarget.IndexOf(animal2), adj2)
        
        Console.WriteLine("{0}The final string is:{0}{1}", 
                          Environment.NewLine, strTarget)
    End Sub 
End Class 
' Output from the example might appear as follows:
'       The original string is:
'       The fox jumps over the dog.
'       
'       Enter an adjective (or group of adjectives) to describe the fox: ==> bold
'       Enter an adjective (or group of adjectives) to describe the dog: ==> lazy
'       
'       The final string is:
'       The bold fox jumps over the lazy dog.

Comentários

A numeração de índice começa do zero.Index numbering starts from zero.

Este método executa uma pesquisa de palavra (diferencia maiúsculas de minúsculas e sensível à cultura) usando a cultura atual.This method performs a word (case-sensitive and culture-sensitive) search using the current culture. A pesquisa começa na primeira posição de caractere dessa instância e continua até a última posição de caractere.The search begins at the first character position of this instance and continues until the last character position.

Conjuntos de caracteres incluem caracteres ignoráveis, que são caracteres que não são considerados ao durante a realização de uma comparação linguística ou sensível à cultura.Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Em uma pesquisa sensível à cultura, caso value contenha um caractere ignorável, o resultado é equivalente à pesquisa com esse caractere removido.In a culture-sensitive search, if value contains an ignorable character, the result is equivalent to searching with that character removed. Se value consistir apenas em um ou mais caracteres ignoráveis, IndexOf(String) o método sempre retorna 0 (zero) para indicar que a correspondência é encontrada no início da instância atual.If value consists only of one or more ignorable characters, the IndexOf(String) method always returns 0 (zero) to indicate that the match is found at the beginning of the current instance. No exemplo a seguir, o IndexOf(String) método é usado para encontrar três subcadeias de caracteres (um hífen simples (U + 00AD), um hífen reversível seguido por "n" e um hífen, seguido por "m") em duas cadeias de caracteres.In the following example, the IndexOf(String) method is used to find three substrings (a soft hyphen (U+00AD), a soft hyphen followed by "n", and a soft hyphen followed by "m") in two strings. Apenas uma das cadeias de caracteres contém um hífen condicional.Only one of the strings contains a soft hyphen. Se o exemplo for executado no .NET Framework 4.NET Framework 4 ou posterior, em cada caso, como o hífen suave é um caractere ignorável, o resultado será o mesmo de se o hífen flexível não tivesse sido incluído no. valueIf the example is run on the .NET Framework 4.NET Framework 4 or later, in each case, because the soft hyphen is an ignorable character, the result is the same as if the soft hyphen had not been included in value. Ao pesquisar apenas um hífen suave, o método retorna 0 (zero) para indicar que encontrou uma correspondência no início da cadeia de caracteres.When searching for a soft hyphen only, the method returns 0 (zero) to indicate that it has found a match at the beginning of the string.

using System;

public class Example
{
    public static void Main()
    {
        string s1 = "ani\u00ADmal";
        string s2 = "animal";
      
        // Find the index of the soft hyphen.
        Console.WriteLine(s1.IndexOf("\u00AD"));
        Console.WriteLine(s2.IndexOf("\u00AD"));
      
        // Find the index of the soft hyphen followed by "n".
        Console.WriteLine(s1.IndexOf("\u00ADn"));
        Console.WriteLine(s2.IndexOf("\u00ADn"));
      
        // Find the index of the soft hyphen followed by "m".
        Console.WriteLine(s1.IndexOf("\u00ADm"));
        Console.WriteLine(s2.IndexOf("\u00ADm"));

        // The example displays the following output
        // if run under the .NET Framework 4 or later:
        //       0
        //       0
        //       1
        //       1
        //       4
        //       3
    }
}
Module Example
   Public Sub Main()
      Dim softHyphen As String = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the soft hyphen.
      Console.WriteLine(s1.IndexOf(softHyphen))
      Console.WriteLine(s2.IndexOf(softHyphen))
      
      ' Find the index of the soft hyphen followed by "n".
      Console.WriteLine(s1.IndexOf(softHyphen + "n"))
      Console.WriteLine(s2.IndexOf(softHyphen + "n"))
      
      ' Find the index of the soft hyphen followed by "m".
      Console.WriteLine(s1.IndexOf(softHyphen + "m"))
      Console.WriteLine(s2.IndexOf(softHyphen + "m"))
   End Sub
End Module
' The example displays the following output 
' if run under the .NET Framework 4 or later:
'       0
'       0
'       1
'       1
'       4
'       3

Notas aos Chamadores

Conforme explicado nas práticas recomendadas para usar cadeias decaracteres, é recomendável evitar a chamada de métodos de comparação de cadeia que substituem valores padrão e, em vez disso, chamam métodos que exigem que os parâmetros sejam especificados explicitamente.As explained in Best Practices for Using Strings, we recommend that you avoid calling string comparison methods that substitute default values and instead call methods that require parameters to be explicitly specified. Para localizar o primeiro índice de uma subcadeia de caracteres dentro de uma instância de cadeia de caracteres usando as regras de comparação da IndexOf(String, StringComparison) cultura atual, chame o método CurrentCulture Overload com comparisonType um valor de para seu parâmetro.To find the first index of a substring within a string instance by using the comparison rules of the current culture, call the IndexOf(String, StringComparison) method overload with a value of CurrentCulture for its comparisonType parameter.

Veja também

IndexOf(Char) IndexOf(Char) IndexOf(Char) IndexOf(Char)

Relata o índice baseado em zero da primeira ocorrência do caractere Unicode especificado na cadeia de caracteres.Reports the zero-based index of the first occurrence of the specified Unicode character in this string.

public:
 int IndexOf(char value);
public int IndexOf (char value);
member this.IndexOf : char -> int
Public Function IndexOf (value As Char) As Integer

Parâmetros

value
Char Char Char Char

Um caractere Unicode a ser buscado.A Unicode character to seek.

Retornos

A posição do índice com base em zero de value caso o caractere seja encontrado -1 caso não seja.The zero-based index position of value if that character is found, or -1 if it is not.

Exemplos

O exemplo a seguir demonstra como você pode pesquisar String um caractere usando o IndexOf método.The following example demonstrates how you can search a String for a character using the IndexOf method.

using namespace System;

void main()
{
   // Create a Unicode String with 5 Greek Alpha characters.
   String^ szGreekAlpha = gcnew String(L'\x0391',5);

   // Create a Unicode String with a 3 Greek Omega characters.
   String^ szGreekOmega = L"\x03A9\x03A9\x03A9";

   String^ szGreekLetters = String::Concat(szGreekOmega, szGreekAlpha, 
                                           szGreekOmega->Clone());

   // Display the entire string.
   Console::WriteLine(szGreekLetters);

   // The first index of Alpha.
   int ialpha = szGreekLetters->IndexOf( L'\x0391');
   // The first index of Omega.
   int iomega = szGreekLetters->IndexOf(L'\x03A9');

   Console::WriteLine("First occurrence of the Greek letter Alpha: Index {0}", 
                      ialpha);
   Console::WriteLine("First occurrence of the Greek letter Omega: Index {0}", 
                      iomega);
}
// The example displays the following output:
//       The string: OOO?????OOO
//       First occurrence of the Greek letter Alpha: Index 3
//       First occurrence of the Greek letter Omega: Index 0
// Create a Unicode string with 5 Greek Alpha characters.
String szGreekAlpha = new String('\u0391',5);

// Create a Unicode string with 3 Greek Omega characters.
String szGreekOmega = "\u03A9\u03A9\u03A9";

String szGreekLetters = String.Concat(szGreekOmega, szGreekAlpha, 
                                    szGreekOmega.Clone());

// Display the entire string.
Console.WriteLine("The string: {0}", szGreekLetters);

// The first index of Alpha.
int ialpha = szGreekLetters.IndexOf('\u0391');
// The first index of Omega.
int iomega = szGreekLetters.IndexOf('\u03A9');

Console.WriteLine("First occurrence of the Greek letter Alpha: Index {0}", 
                ialpha);
Console.WriteLine("First occurrence of the Greek letter Omega: Index {0}", 
                iomega);

// The example displays the following output:
//    The string: ΩΩΩΑΑΑΑΑΩΩΩ
//    First occurrence of the Greek letter Alpha: Index 3
//    First occurrence of the Greek letter Omega: Index 0
Public Module Example
   Public Sub Main()
      ' Create a Unicode string with 5 Greek Alpha characters.
      Dim szGreekAlpha As New String(ChrW(&H0391), 5)

      ' Create a Unicode string with 3 Greek Omega characters.
      Dim szGreekOmega As String = ChrW(&H03A9) + ChrW(&H03A9)+
                                   ChrW(&H03A9)

      Dim szGreekLetters As String = String.Concat(szGreekOmega, szGreekAlpha, _
                                                   szGreekOmega.Clone())

      ' Display the entire string.
      Console.WriteLine(szGreekLetters)

      ' The first index of Alpha.
      Dim iAlpha As Integer = szGreekLetters.IndexOf(ChrW(&H0391))
      ' The first index of Omega.
      Dim iomega As Integer = szGreekLetters.IndexOf(ChrW(&H03A9))

      Console.WriteLine("First occurrence of the Greek letter Alpha: Index {0}", 
                        ialpha)
      Console.WriteLine("First occurrence of the Greek letter Omega: Index {0}", 
                        iomega)
   End Sub
End Module
' The example displays the following output:
'       The string: OOO?????OOO
'       First occurrence of the Greek letter Alpha: Index 3
'       First occurrence of the Greek letter Omega: Index 0

Comentários

A numeração de índice começa do zero.Index numbering starts from zero.

Este método executa uma pesquisa ordinal (insensível à cultura), onde um caractere só é considerado equivalente a um outro caractere caso os valores escalares Unicode sejam os mesmos.This method performs an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if their Unicode scalar values are the same. Para executar uma pesquisa sensível à cultura, use o método CompareInfo.IndexOf, em que um valor escalar Unicode representando um caractere pré-composto como a ligadura "Æ" (U+00C6) pode ser considerado equivalente a qualquer ocorrência dos componentes do caractere na sequência correta, como "AE" (U+0041, U+0045), dependendo da cultura.To perform a culture-sensitive search, use the CompareInfo.IndexOf method, where a Unicode scalar value representing a precomposed character, such as the ligature "Æ" (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture.

Veja também

IndexOf(String, Int32) IndexOf(String, Int32) IndexOf(String, Int32) IndexOf(String, Int32)

Relata o índice baseado em zero da primeira ocorrência da cadeia de caracteres especificada nessa instância.Reports the zero-based index of the first occurrence of the specified string in this instance. A pesquisa é iniciada em uma posição de caractere especificada.The search starts at a specified character position.

public:
 int IndexOf(System::String ^ value, int startIndex);
public int IndexOf (string value, int startIndex);
member this.IndexOf : string * int -> int
Public Function IndexOf (value As String, startIndex As Integer) As Integer

Parâmetros

value
String String String String

A cadeia de caracteres a ser buscada.The string to seek.

startIndex
Int32 Int32 Int32 Int32

A posição inicial da pesquisa.The search starting position.

Retornos

A posição de índice baseado em zero do value do início da instância atual se essa cadeia de caracteres for encontrada; caso contrário, -1.The zero-based index position of value from the start of the current instance if that string is found, or -1 if it is not. Se value for Empty, o valor retornado será startIndex.If value is Empty, the return value is startIndex.

Exceções

startIndex é menor que 0 (zero) ou maior que o tamanho dessa cadeia de caracteres.startIndex is less than 0 (zero) or greater than the length of this string.

Exemplos

O exemplo a seguir pesquisa todas as ocorrências de uma cadeia de caracteres especificada em uma cadeia de caracteres de destino.The following example searches for all occurrences of a specified string within a target string.

using namespace System;
int main()
{
   String^ strSource = "This is the string which we will perform the search on";
   Console::WriteLine( "The search string is: {0}\"{1}\" {0}", Environment::NewLine, strSource );
   String^ strTarget = "";
   int found = 0;
   int totFinds = 0;
   do
   {
      Console::Write( "Please enter a search value to look for in the above string (hit Enter to exit) ==> " );
      strTarget = Console::ReadLine();
      if (  !strTarget->Equals( "" ) )
      {
         for ( int i = 0; i < strSource->Length; i++ )
         {
            found = strSource->IndexOf( strTarget, i );
            if (found >= 0)
            {
               totFinds++;
               i = found;
            }
            else
               break;

         }
      }
      else
            return 0;
      Console::WriteLine( "{0}The search parameter '{1}' was found {2} times. {0}", Environment::NewLine, strTarget, totFinds );
      totFinds = 0;
   }
   while ( true );
}

using System;

public class IndexOfTest {
    public static void Main() {

        string strSource = "This is the string which we will perform the search on";

        Console.WriteLine("The search string is:{0}\"{1}\"{0}", Environment.NewLine, strSource);

        string strTarget = "";
        int found = 0;
        int totFinds = 0;

        do {
            Console.Write("Please enter a search value to look for in the above string (hit Enter to exit) ==> ");

            strTarget = Console.ReadLine();

            if (strTarget != "") {

                for (int i = 0; i < strSource.Length; i++) {

                    found = strSource.IndexOf(strTarget, i);

                    if (found >= 0) {
                        totFinds++;
                        i = found;
                    }
                    else
                        break;
                }
            }
            else
                return;

            Console.WriteLine("{0}The search parameter '{1}' was found {2} times.{0}",
                    Environment.NewLine, strTarget, totFinds);

            totFinds = 0;

        } while ( true );
    }
}
Imports System

Public Class IndexOfTest
    
    Public Shared Sub Main()
        Dim strSource As String = "This is the string which we will perform the search on"
        
        Console.WriteLine("The search string is:{0}{1}{0}", Environment.NewLine, strSource)
        Dim strTarget As String = ""
        Dim found As Integer = 0
        Dim totFinds As Integer = 0
        
        Do
            Console.Write("Please enter a search value to look for in the above string (hit Enter to exit) ==> ")
            
            strTarget = Console.ReadLine()
            If strTarget <> "" Then
                Dim i As Integer
                
                
                For i = 0 To strSource.Length - 1
                    
                    found = strSource.IndexOf(strTarget, i)
                    If found >= 0 Then
                        
                        totFinds += 1
                        i = found
                    Else
                        Exit For
                    End If
                Next i
            Else
                Return
            
            End If
            Console.WriteLine("{0}The search parameter '{1}' was found {2} times.{0}", Environment.NewLine, strTarget, totFinds)
            
            totFinds = 0
        
        Loop While True
    End Sub 'Main
End Class 'IndexOfTest

Comentários

A numeração de índice começa em 0.Index numbering starts from 0. O parâmetro startIndex pode variar de 0 ao tamanho da instância da cadeia de caracteres.The startIndex parameter can range from 0 to the length of the string instance. Se startIndex for igual ao comprimento da instância de cadeia de caracteres, o método retornará-1.If startIndex equals the length of the string instance, the method returns -1.

Este método executa uma pesquisa de palavra (diferencia maiúsculas de minúsculas e sensível à cultura) usando a cultura atual.This method performs a word (case-sensitive and culture-sensitive) search using the current culture. A pesquisa começa na startIndex posição de caracteres dessa instância e continua até a última posição de caractere.The search begins at the startIndex character position of this instance and continues until the last character position.

Conjuntos de caracteres incluem caracteres ignoráveis, que são caracteres que não são considerados ao durante a realização de uma comparação linguística ou sensível à cultura.Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. Em uma pesquisa sensível à cultura, caso value contenha um caractere ignorável, o resultado é equivalente à pesquisa com esse caractere removido.In a culture-sensitive search, if value contains an ignorable character, the result is equivalent to searching with that character removed. Se value consistir apenas em um ou mais caracteres ignoráveis, IndexOf(String, Int32) o método sempre startIndexretornará, que é a posição do caractere na qual a pesquisa começa.If value consists only of one or more ignorable characters, the IndexOf(String, Int32) method always returns startIndex, which is the character position at which the search begins. No exemplo a seguir, o IndexOf(String, Int32) método é usado para localizar a posição de um hífen flexível (U + 00AD) seguido por um "m" em duas cadeias de caracteres.In the following example, the IndexOf(String, Int32) method is used to find the position of a soft hyphen (U+00AD) followed by an "m" in two strings. Apenas uma das cadeias de caracteres contém a subcadeia de caracteres necessária.Only one of the strings contains the required substring. Se o exemplo for executado no .NET Framework 4.NET Framework 4 ou posterior, em ambos os casos, como o hífen suave é um caractere ignorável, o método retornará o índice de "m" na cadeia de caracteres.If the example is run on the .NET Framework 4.NET Framework 4 or later, in both cases, because the soft hyphen is an ignorable character, the method returns the index of "m" in the string. No caso da primeira cadeia de caracteres, que inclui o hífen condicional seguido de um "m", o método não retorna o índice do hífen virtual, mas retorna o índice do "m".Note that in the case of the first string, which includes the soft hyphen followed by an "m", the method fails to return the index of the soft hyphen but instead returns the index of the "m".

using System;

public class Example
{
    public static void Main()
    {
        string searchString = "\u00ADm";
        string s1 = "ani\u00ADmal" ;
        string s2 = "animal";

        Console.WriteLine(s1.IndexOf(searchString, 2));
        Console.WriteLine(s2.IndexOf(searchString, 2));

        // The example displays the following output:
        //       4
        //       3
    }
}
Module Example
   Public Sub Main()
      Dim searchString As String = Chrw(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"

      Console.WriteLine(s1.IndexOf(searchString, 2))
      Console.WriteLine(s2.IndexOf(searchString, 2))
   End Sub
End Module
' The example displays the following output:
'       4
'       3 

Notas aos Chamadores

Conforme explicado nas práticas recomendadas para usar cadeias decaracteres, é recomendável evitar a chamada de métodos de comparação de cadeia que substituem valores padrão e, em vez disso, chamam métodos que exigem que os parâmetros sejam especificados explicitamente.As explained in Best Practices for Using Strings, we recommend that you avoid calling string comparison methods that substitute default values and instead call methods that require parameters to be explicitly specified. Para localizar o primeiro índice de uma subcadeia de caracteres que ocorre após uma determinada posição de caractere usando as regras de comparação da cultura atual, IndexOf(String, Int32, StringComparison) chame o método Overload com um CurrentCulture valor de comparisonType para seu parâmetro.To find the first index of a substring that occurs after a particular character position by using the comparison rules of the current culture, call the IndexOf(String, Int32, StringComparison) method overload with a value of CurrentCulture for its comparisonType parameter.

Veja também

Aplica-se a