StringCollection.IndexOf(String) StringCollection.IndexOf(String) StringCollection.IndexOf(String) StringCollection.IndexOf(String) Method

Определение

Осуществляет поиск указанной строки и возвращает отсчитываемый от нуля индекс ее первого вхождения в коллекцию StringCollection.Searches for the specified string and returns the zero-based index of the first occurrence within the StringCollection.

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

Параметры

value
String String String String

Строка для поиска.The string to locate. Допускается значение null.The value can be null.

Возвраты

Отсчитываемый от нуля индекс первого вхождения value в StringCollection, если он найден; в противном случае — значение -1.The zero-based index of the first occurrence of value in the StringCollection, if found; otherwise, -1.

Примеры

В следующем примере кода выполняется поиск StringCollection элемента в.The following code example searches the StringCollection for an element.

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintValues( IEnumerable^ myCol );
int main()
{
   
   // Creates and initializes a new StringCollection.
   StringCollection^ myCol = gcnew StringCollection;
   array<String^>^myArr = {"RED","orange","yellow","RED","green","blue","RED","indigo","violet","RED"};
   myCol->AddRange( myArr );
   Console::WriteLine( "Initial contents of the StringCollection:" );
   PrintValues( myCol );
   
   // Checks whether the collection contains "orange" and, if so, displays its index.
   if ( myCol->Contains( "orange" ) )
      Console::WriteLine( "The collection contains \"orange\" at index {0}.", myCol->IndexOf( "orange" ) );
   else
      Console::WriteLine( "The collection does not contain \"orange\"." );
}

void PrintValues( IEnumerable^ myCol )
{
   IEnumerator^ myEnum = myCol->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::WriteLine( "   {0}", obj );
   }

   Console::WriteLine();
}

/*
This code produces the following output.

Initial contents of the StringCollection:
   RED
   orange
   yellow
   RED
   green
   blue
   RED
   indigo
   violet
   RED

The collection contains "orange" at index 1.

*/
using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesStringCollection  {

   public static void Main()  {

      // Creates and initializes a new StringCollection.
      StringCollection myCol = new StringCollection();
      String[] myArr = new String[] { "RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED" };
      myCol.AddRange( myArr );

      Console.WriteLine( "Initial contents of the StringCollection:" );
      PrintValues( myCol );

      // Checks whether the collection contains "orange" and, if so, displays its index.
      if ( myCol.Contains( "orange" ) )
         Console.WriteLine( "The collection contains \"orange\" at index {0}.", myCol.IndexOf( "orange" ) );
      else
         Console.WriteLine( "The collection does not contain \"orange\"." );

   }

   public static void PrintValues( IEnumerable myCol )  {
      foreach ( Object obj in myCol )
         Console.WriteLine( "   {0}", obj );
      Console.WriteLine();
   }

}

/*
This code produces the following output.

Initial contents of the StringCollection:
   RED
   orange
   yellow
   RED
   green
   blue
   RED
   indigo
   violet
   RED

The collection contains "orange" at index 1.

*/
Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesStringCollection   

   Public Shared Sub Main()

      ' Creates and initializes a new StringCollection.
      Dim myCol As New StringCollection()
      Dim myArr() As [String] = {"RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED"}
      myCol.AddRange(myArr)

      Console.WriteLine("Initial contents of the StringCollection:")
      PrintValues(myCol)

      ' Checks whether the collection contains "orange" and, if so, displays its index.
      If myCol.Contains("orange") Then
         Console.WriteLine("The collection contains ""orange"" at index {0}.", myCol.IndexOf("orange"))
      Else
         Console.WriteLine("The collection does not contain ""orange"".")
      End If 

   End Sub

   Public Shared Sub PrintValues(myCol As IEnumerable)
      Dim obj As [Object]
      For Each obj In  myCol
         Console.WriteLine("   {0}", obj)
      Next obj
      Console.WriteLine()
   End Sub

End Class


'This code produces the following output.
'
'Initial contents of the StringCollection:
'   RED
'   orange
'   yellow
'   RED
'   green
'   blue
'   RED
'   indigo
'   violet
'   RED
'
'The collection contains "orange" at index 1.
'

Комментарии

Этот метод определяет равенство путем Object.Equalsвызова.This method determines equality by calling Object.Equals. При сравнении строк учитывается регистр.String comparisons are case-sensitive.

Этот метод выполняет линейный поиск. Таким образом, этот метод является операциейnO (), n где Countимеет.This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

Начиная с .NET Framework 2,0, этот метод использует объекты Equals и CompareTo методы item коллекции для определения того, существует ли элемент.Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. В более ранних версиях .NET Framework это определение было выполнено с помощью Equals методов item и CompareTo параметра для объектов в коллекции.In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.

Применяется к

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