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

Definisi

Ruang nama:

System.Collections.Generic

Rakitan:

System.Collections.dll

Sumber:

Dictionary.cs

Menentukan apakah IDictionary berisi elemen dengan kunci yang ditentukan.

 virtual bool System.Collections.IDictionary.Contains(System::Object ^ key) = System::Collections::IDictionary::Contains;

bool IDictionary.Contains (object key);

abstract member System.Collections.IDictionary.Contains : obj -> bool
override this.System.Collections.IDictionary.Contains : obj -> bool

Function Contains (key As Object) As Boolean Implements IDictionary.Contains

Parameter

key

Object

Kunci untuk menemukan di IDictionary.

Mengembalikan

Boolean

trueIDictionary jika berisi elemen dengan kunci yang ditentukan; jika tidak, false.

Penerapan

Contains(Object)

Pengecualian

ArgumentNullException

keyadalah null.

Contoh

Contoh kode berikut menunjukkan cara menggunakan IDictionary.Contains metode System.Collections.IDictionary antarmuka dengan Dictionary<TKey,TValue>. Contoh menunjukkan bahwa metode mengembalikan false jika kunci jenis data yang salah disediakan.

Contoh kode adalah bagian dari contoh yang lebih besar, termasuk output, yang disediakan untuk metode .IDictionary.Add

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

Keterangan

Metode ini mengembalikan false jika key adalah jenis yang tidak dapat ditetapkan ke jenis TKeyDictionary<TKey,TValue>kunci .

Metode ini mendekati operasi O(1).