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

次のコード例は、 IDictionary.Contains System.Collections.IDictionaryインターフェイスのメソッドをと共Dictionary<TKey,TValue>に使用する方法を示しています。The following code example shows how to use the IDictionary.Contains method of the System.Collections.IDictionary interface with a Dictionary<TKey,TValue>. この例では、間違ったfalseデータ型のキーが指定された場合に、メソッドからが返されることを示しています。The example demonstrates that the method returns false if a key of the wrong data type is supplied.

このコード例は、 IDictionary.Addメソッドに指定された出力を含む、より大きな例の一部です。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.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

がのキー falsekey TKey に代入できない型の場合、このメソッドはDictionary<TKey,TValue>を返します。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) 操作にアプローチします。This method approaches an O(1) operation.

適用対象