Dictionary<TKey,TValue>.IDictionary.Contains(Object) Dictionary<TKey,TValue>.IDictionary.Contains(Object) Dictionary<TKey,TValue>.IDictionary.Contains(Object) Method

定義

指定したキーの要素が IDictionary に格納されているかどうかを確認します。Determines whether the IDictionary contains an element with the specified key.

 virtual bool System.Collections.IDictionary.Contains(System::Object ^ key) = System::Collections::IDictionary::Contains;
bool IDictionary.Contains (object key);
Function Contains (key As Object) As Boolean Implements IDictionary.Contains

パラメーター

key
Object Object Object

IDictionary 内で検索されるキー。The key to locate in the IDictionary.

戻り値

指定したキーを持つ要素が true に格納されている場合は IDictionary。それ以外の場合は falsetrue if the IDictionary contains an element with the specified key; otherwise, false.

実装

例外

次のコード例を使用する方法を示しています、IDictionary.Containsのメソッド、System.Collections.IDictionaryとのインターフェイスをDictionary<TKey,TValue>します。The following code example shows how to use the IDictionary.Contains method of the System.Collections.IDictionary interface with a Dictionary<TKey,TValue>. 例を示しますが、メソッドを返すfalse無効なデータ型のキーを指定した場合。The example demonstrates that the method returns false if a key of the wrong data type is supplied.

指定された出力より大きな例のコード例は、IDictionary.Addメソッド。The code example is part of a larger example, including output, provided for the IDictionary.Add method.

using System;
using System.Collections;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new dictionary of strings, with string keys,
        // and access it using the IDictionary interface.
        //
        IDictionary openWith = new Dictionary<string, string>();

        // Add some elements to the dictionary. There are no 
        // duplicate keys, but some of the values are duplicates.
        // IDictionary.Add throws an exception if incorrect types
        // are supplied for key or value.
        openWith.Add("txt", "notepad.exe");
        openWith.Add("bmp", "paint.exe");
        openWith.Add("dib", "paint.exe");
        openWith.Add("rtf", "wordpad.exe");
Imports System
Imports System.Collections
Imports System.Collections.Generic

Public Class Example
    
    Public Shared Sub Main() 

        ' Create a new dictionary of strings, with string keys,
        ' and access it using the IDictionary interface.
        '
        Dim openWith As IDictionary = _
            New Dictionary(Of String, String)
        
        ' Add some elements to the dictionary. There are no 
        ' duplicate keys, but some of the values are duplicates.
        ' IDictionary.Add throws an exception if incorrect types
        ' are supplied for key or value.
        openWith.Add("txt", "notepad.exe")
        openWith.Add("bmp", "paint.exe")
        openWith.Add("dib", "paint.exe")
        openWith.Add("rtf", "wordpad.exe")
// Contains can be used to test keys before inserting 
// them.
if (!openWith.Contains("ht"))
{
    openWith.Add("ht", "hypertrm.exe");
    Console.WriteLine("Value added for key = \"ht\": {0}", 
        openWith["ht"]);
}

// IDictionary.Contains returns false if the wrong data
// type is supplied.
Console.WriteLine("openWith.Contains(29.7) returns {0}",
    openWith.Contains(29.7));
' Contains can be used to test keys before inserting 
' them.
If Not openWith.Contains("ht") Then
    openWith.Add("ht", "hypertrm.exe")
    Console.WriteLine("Value added for key = ""ht"": {0}", _
        openWith("ht"))
End If

' IDictionary.Contains returns False if the wrong data 
' type is supplied.
Console.WriteLine("openWith.Contains(29.7) returns {0}", _
    openWith.Contains(29.7))
    }
}

    End Sub

End Class

注釈

このメソッドが戻るfalse場合keyがキー型に割り当てることはできません型のTKeyDictionary<TKey,TValue>します。This method returns false if key is of a type that is not assignable to the key type TKey of the Dictionary<TKey,TValue>.

このメソッドは、o (1) 操作に近くなります。This method approaches an O(1) operation.

適用対象