Hashtable.Contains メソッド

.NET Framework クラス ライブラリ リファレンス

Hashtable.Contains メソッド

Hashtable に特定のキーが格納されているかどうかを判断します。

名前空間: System.Collections
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Public Overridable Function
 Contains ( _
    key As Object _
) As Boolean

Visual Basic (使用法)

Dim instance As Hashtable
Dim key As Object
Dim returnValue As Boolean

returnValue = instance.Contains(key)

C#

public virtual bool Contains (
    Object key
)

C++

public:
virtual bool Contains (
    Object^ key
)

J#

public boolean Contains (
    Object key
)

JScript

public function Contains (
    key : Object
) : boolean

パラメータ

key

Hashtable 内で検索されるキー。

戻り値
指定したキーを持つ要素が Hashtable に格納されている場合は true。それ以外の場合は false。

例外

例外の種類	条件
ArgumentNullException	key が null 参照 (Visual Basic では Nothing) です。

解説

Contains は、IDictionary.Contains を実装します。これは、ContainsKey とまったく同じ動作をします。

このメソッドは O(1) 操作です。

使用例

Hashtable に特定の要素が格納されているかどうかを判断する方法の例を次に示します。

Visual Basic

Imports System
Imports System.Collections

Public Class SamplesHashtable

    Public Shared Sub Main()

        ' Creates and initializes a new Hashtable.
        Dim myHT As New
 Hashtable()
        myHT.Add(0, "zero")
        myHT.Add(1, "one")
        myHT.Add(2, "two")
        myHT.Add(3, "three")
        myHT.Add(4, "four")

        ' Displays the values of the Hashtable.
        Console.WriteLine("The Hashtable contains the following
 values:")
        PrintIndexAndKeysAndValues(myHT)

        ' Searches for a specific key.
        Dim myKey As Integer
 = 2
        Console.Write("The key ""{0}""
 is ", myKey)
        If(myHT.ContainsKey(myKey))
           Console.WriteLine("in the Hashtable.")
        Else
           Console.WriteLine("NOT in the Hashtable.")
        End If

        myKey = 6
        Console.Write("The key ""{0}""
 is ", myKey)
        If(myHT.ContainsKey(myKey))
           Console.WriteLine(" in the Hashtable.")
        Else
           Console.WriteLine(" NOT in the Hashtable.")
        End If

        ' Searches for a specific value.
        Dim myValue As String
 = "three"
        Console.Write("The value ""{0}""
 is ", myValue)
        If(myHT.ContainsValue(myValue))
           Console.WriteLine(" in the Hashtable.")
        Else
           Console.WriteLine(" NOT in the Hashtable.")
        End If

        myValue = "nine"
        Console.Write("The value ""{0}""
 is ", myValue)
        If(myHT.ContainsValue(myValue))
           Console.WriteLine(" in the Hashtable.")
        Else
           Console.WriteLine(" NOT in the Hashtable.")
        End If

    End Sub 'Main

    Public Shared Sub PrintIndexAndKeysAndValues(myHT
 As Hashtable)
        Dim i As Integer
 = 0
        Console.WriteLine(vbTab + "-INDEX-" + vbTab
 + "-KEY-" + vbTab + "-VALUE-")
        Dim de As DictionaryEntry
        For Each de In 
 myHT
            Console.WriteLine(vbTab + "[{0}]:" + vbTab
 + "{1}" + vbTab + "{2}",
 i, de.Key, de.Value)
            i = i + 1
        Next de
        Console.WriteLine()
    End Sub 'PrintIndexAndKeysAndValues

End Class 'SamplesHashtable 


' This code produces the following output.
' 
' The Hashtable contains the following values:
'         -INDEX- -KEY-   -VALUE-
'         [0]:    4       four
'         [1]:    3       three
'         [2]:    2       two
'         [3]:    1       one
'         [4]:    0       zero
'
' The key "2" is in the Hashtable.
' The key "6" is NOT in the Hashtable.
' The value "three" is in the Hashtable.
' The value "nine" is NOT in the Hashtable.

C#

using System;
using System.Collections;
public class SamplesHashtable  {

   public static void Main()
  {

      // Creates and initializes a new Hashtable.
      Hashtable myHT = new Hashtable();
      myHT.Add( 0, "zero" );
      myHT.Add( 1, "one" );
      myHT.Add( 2, "two" );
      myHT.Add( 3, "three" );
      myHT.Add( 4, "four" );

      // Displays the values of the Hashtable.
      Console.WriteLine( "The Hashtable contains the following values:"
 );
      PrintIndexAndKeysAndValues( myHT );

      // Searches for a specific key.
      int myKey = 2;
      Console.WriteLine( "The key \"{0}\" is {1}.", myKey, myHT.ContainsKey(
 myKey ) ? "in the Hashtable" : "NOT in
 the Hashtable" );
      myKey = 6;
      Console.WriteLine( "The key \"{0}\" is {1}.", myKey, myHT.ContainsKey(
 myKey ) ? "in the Hashtable" : "NOT in
 the Hashtable" );

      // Searches for a specific value.
      String myValue = "three";
      Console.WriteLine( "The value \"{0}\" is {1}.", myValue,
 myHT.ContainsValue( myValue ) ? "in the Hashtable"
 : "NOT in the Hashtable" );
      myValue = "nine";
      Console.WriteLine( "The value \"{0}\" is {1}.", myValue,
 myHT.ContainsValue( myValue ) ? "in the Hashtable"
 : "NOT in the Hashtable" );
   }


   public static void PrintIndexAndKeysAndValues(
 Hashtable myHT )  {
      int i = 0;
      Console.WriteLine( "\t-INDEX-\t-KEY-\t-VALUE-" );
      foreach ( DictionaryEntry de in myHT
 )
         Console.WriteLine( "\t[{0}]:\t{1}\t{2}", i++, de.Key, de.Value
 );
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

The Hashtable contains the following values:
        -INDEX- -KEY-   -VALUE-
        [0]:    4       four
        [1]:    3       three
        [2]:    2       two
        [3]:    1       one
        [4]:    0       zero

The key "2" is in the Hashtable.
The key "6" is NOT in the Hashtable.
The value "three" is in the Hashtable.
The value "nine" is NOT in the Hashtable.

*/ 

C++

using namespace System;
using namespace System::Collections;
void PrintIndexAndKeysAndValues( Hashtable^ myHT );
int main()
{
   
   // Creates and initializes a new Hashtable.
   Hashtable^ myHT = gcnew Hashtable;
   myHT->Add( (int^)0, "zero" );
   myHT->Add( 1, "one" );
   myHT->Add( 2, "two" );
   myHT->Add( 3, "three" );
   myHT->Add( 4, "four" );
   
   // Displays the values of the Hashtable.
   Console::WriteLine( "The Hashtable contains the following values:" );
   PrintIndexAndKeysAndValues( myHT );
   
   // Searches for a specific key.
   int myKey = 2;
   Console::WriteLine( "The key \"{0}\" is {1}.", myKey, myHT->ContainsKey(
 myKey ) ? (String^)"in the Hashtable" : "NOT
 in the Hashtable" );
   myKey = 6;
   Console::WriteLine( "The key \"{0}\" is {1}.", myKey, myHT->ContainsKey(
 myKey ) ? (String^)"in the Hashtable" : "NOT
 in the Hashtable" );
   
   // Searches for a specific value.
   String^ myValue = "three";
   Console::WriteLine( "The value \"{0}\" is {1}.", myValue,
 myHT->ContainsValue( myValue ) ? (String^)"in the Hashtable"
 : "NOT in the Hashtable" );
   myValue = "nine";
   Console::WriteLine( "The value \"{0}\" is {1}.", myValue,
 myHT->ContainsValue( myValue ) ? (String^)"in the Hashtable"
 : "NOT in the Hashtable" );
}

void PrintIndexAndKeysAndValues( Hashtable^ myHT )
{
   int i = 0;
   Console::WriteLine( "\t-INDEX-\t-KEY-\t-VALUE-" );
   IEnumerator^ myEnum = myHT->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      DictionaryEntry de =  *safe_cast<DictionaryEntry ^>(myEnum->Current);
      Console::WriteLine( "\t[{0}]:\t{1}\t{2}", i++, de.Key, de.Value );
   }

   Console::WriteLine();
}

/* 
 This code produces the following output.
 
 The Hashtable contains the following values:
         -INDEX- -KEY-   -VALUE-
         [0]:    4       four
         [1]:    3       three
         [2]:    2       two
         [3]:    1       one
         [4]:    0       zero

 The key "2" is in the Hashtable.
 The key "6" is NOT in the Hashtable.
 The value "three" is in the Hashtable.
 The value "nine" is NOT in the Hashtable.

 */

J#

import System.*;
import System.Collections.*;

public class SamplesHashtable
{
    public static void main(String[]
 args)
    {
        // Creates and initializes a new Hashtable.
        Hashtable myHT = new Hashtable();

        myHT.Add(new Integer(0), "zero");
        myHT.Add(new Integer(1), "one");
        myHT.Add(new Integer(2), "two");
        myHT.Add(new Integer(3), "three");
        myHT.Add(new Integer(4), "four");

        // Displays the values of the Hashtable.
        Console.WriteLine("The Hashtable contains the following values:");
        PrintIndexAndKeysAndValues(myHT);

        // Searches for a specific key.
        int myKey = 2;

        Console.WriteLine("The key \"{0}\" is {1}.", 
            System.Convert.ToString(myKey), 
            (myHT.ContainsKey(new Integer(myKey))) ? 
            "in the Hashtable" : "NOT in
 the Hashtable");
        myKey = 6;
        Console.WriteLine("The key \"{0}\" is {1}.", 
            System.Convert.ToString(myKey), 
            (myHT.ContainsKey(new Integer(myKey))) ? 
            "in the Hashtable" : "NOT in
 the Hashtable");

        // Searches for a specific value.
        String myValue = "three";

        Console.WriteLine("The value \"{0}\" is {1}.", myValue,
 
            (myHT.ContainsValue(myValue)) ? 
            "in the Hashtable" : "NOT in
 the Hashtable");
        myValue = "nine";
        Console.WriteLine("The value \"{0}\" is {1}.", myValue,
 
            (myHT.ContainsValue(myValue)) ? 
            "in the Hashtable" : "NOT in
 the Hashtable");
    } //main

    public static void PrintIndexAndKeysAndValues(Hashtable
 myHT)
    {
        int i = 0;
        Console.WriteLine("\t-INDEX-\t-KEY-\t-VALUE-");
        IEnumerator myEnumerator = myHT.GetEnumerator();

        while (myEnumerator.MoveNext()) {
            DictionaryEntry de = (DictionaryEntry)myEnumerator.get_Current();
            Console.WriteLine("\t[{0}]:\t{1}\t{2}", 
                System.Convert.ToString(i++), 
                de.get_Key().toString(), de.get_Value().toString());
        }
        Console.WriteLine();
    } //PrintIndexAndKeysAndValues
} //SamplesHashtable 

/* 
 This code produces the following output.
 
 The Hashtable contains the following values:
         -INDEX- -KEY-   -VALUE-
         [0]:    4       four
         [1]:    3       three
         [2]:    2       two
         [3]:    1       one
         [4]:    0       zero

 The key "2" is in the Hashtable.
 The key "6" is NOT in the Hashtable.
 The value "three" is in the Hashtable.
 The value "nine" is NOT in the Hashtable.
 */

JScript

import System
import System.Collections
import Microsoft.VisualBasic

// Creates and initializes a new Hashtable.
var myHT : Hashtable = new Hashtable()
myHT.Add(0, "zero")
myHT.Add(1, "one")
myHT.Add(2, "two")
myHT.Add(3, "three")
myHT.Add(4, "four")

// Displays the values of the Hashtable.
Console.WriteLine("The Hashtable contains the following values:")
PrintIndexAndKeysAndValues(myHT)

// Searches for a specific key.
var msg : String
var myKey : int = 2
if(myHT.ContainsKey(myKey))
    msg = "in the Hashtable"
else
    msg = "NOT in the Hashtable"
Console.WriteLine("The key \"{0}\" is {1}.", myKey, msg)
myKey = 6
if(myHT.ContainsKey(myKey))
    msg = "in the Hashtable"
else
    msg = "NOT in the Hashtable"
Console.WriteLine("The key \"{0}\" is {1}.", myKey, msg)

// Searches for a specific value.
var myValue : String = "three"
if(myHT.ContainsValue(myValue))
    msg = "in the Hashtable"
else
    msg = "NOT in the Hashtable"
Console.WriteLine("The value \"{0}\" is {1}.", myValue, msg)
myValue = "nine"
if(myHT.ContainsValue(myValue))
    msg = "in the Hashtable"
else
    msg = "NOT in the Hashtable"
Console.WriteLine("The value \"{0}\" is {1}.", myValue, msg)

function PrintIndexAndKeysAndValues(myList : Hashtable){
    var myEnumerator : IDictionaryEnumerator = myList.GetEnumerator()
    var i : int = 0
    Console.WriteLine("\t-INDEX-\t-KEY-\t-VALUE-")
    while(myEnumerator.MoveNext()){
        Console.WriteLine("\t[{0}]:\t{1}\t{2}", i++, myEnumerator.Key,
            myEnumerator.Value)
    }
    Console.WriteLine()
}

// This code produces the following output.
// 
// The Hashtable contains the following values:
//     -INDEX-    -KEY-    -VALUE-
//     [0]:       4        four
//     [1]:       3        three
//     [2]:       2        two
//     [3]:       1        one
//     [4]:       0        zero
// 
// The key "2" is in the Hashtable.
// The key "6" is NOT in the Hashtable.
// The value "three" is in the Hashtable.
// The value "nine" is NOT in the Hashtable. 

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
Hashtable クラス
Hashtable メンバ
System.Collections 名前空間
ContainsKey
IDictionary