StringCollection.IndexOf(String) メソッド

定義

指定した文字列を検索し、StringCollection 内でその文字列が最初に見つかった位置の 0 から始まるインデックスを返します。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);
public int IndexOf (string? value);
member this.IndexOf : string -> int
Public Function IndexOf (value As String) As Integer

パラメーター

value
String

検索される文字列。The string to locate. 値として null を指定できます。The value can be null.

戻り値

Int32

StringCollection 内で value が見つかった場合は、最初に見つかった位置の 0 から始まるインデックス。それ以外の場合は -1。The zero-based index of the first occurrence of value in the StringCollection, if found; otherwise, -1.

次のコード例では、で StringCollection 要素を検索します。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.
'

注釈

このメソッドは、を呼び出すことによって等価性を判断し Object.Equals ます。This method determines equality by calling Object.Equals. 文字列比較では大文字と小文字が区別されます。String comparisons are case-sensitive.

このメソッドは、線形検索を実行します。したがって、このメソッドは O ( n ) 演算です。ここで、 nCount です。This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

.NET Framework 2.0 以降では、このメソッドは、コレクションのオブジェクトとメソッドを使用して、 Equals CompareTo item 項目が存在するかどうかを判断します。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. 以前のバージョンの .NET Framework では、この決定は、 Equals CompareTo コレクション内のオブジェクトのパラメーターのメソッドとメソッドを使用して行われていま item した。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.

適用対象

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