Bagikan melalui

ListDictionary.Add(Object, Object) Metode

  • Referensi

Definisi

Ruang nama:
System.Collections.Specialized
Rakitan:
System.dll, System.Collections.Specialized.dll
Rakitan:
System.Collections.Specialized.dll
Rakitan:
System.dll
Rakitan:
netstandard.dll
Sumber:
ListDictionary.cs
Sumber:
ListDictionary.cs
Sumber:
ListDictionary.cs

Menambahkan entri dengan kunci dan nilai yang ditentukan ke ListDictionarydalam .

public:
 virtual void Add(System::Object ^ key, System::Object ^ value);
public void Add (object key, object value);
public void Add (object key, object? value);
abstract member Add : obj * obj -> unit
override this.Add : obj * obj -> unit
Public Sub Add (key As Object, value As Object)

Parameter

key
Object

Kunci entri yang akan ditambahkan.

value
Object

Nilai entri yang akan ditambahkan. Nilainya bisa null.

Penerapan

Add(Object, Object)

Pengecualian

ArgumentNullException

keyadalah null.

ArgumentException

Entri dengan kunci yang sama sudah ada di ListDictionary.

Contoh

Contoh kode berikut menambahkan ke dan menghapus elemen dari ListDictionary.

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintKeysAndValues( IDictionary^ myCol )
{
   Console::WriteLine( "   KEY                       VALUE" );
   IEnumerator^ myEnum = myCol->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      DictionaryEntry de = safe_cast<DictionaryEntry>(myEnum->Current);
      Console::WriteLine( "   {0,-25} {1}", de.Key, de.Value );
   }

   Console::WriteLine();
}

int main()
{
   
   // Creates and initializes a new ListDictionary.
   ListDictionary^ myCol = gcnew ListDictionary;
   myCol->Add( "Braeburn Apples", "1.49" );
   myCol->Add( "Fuji Apples", "1.29" );
   myCol->Add( "Gala Apples", "1.49" );
   myCol->Add( "Golden Delicious Apples", "1.29" );
   myCol->Add( "Granny Smith Apples", "0.89" );
   myCol->Add( "Red Delicious Apples", "0.99" );
   
   // Displays the values in the ListDictionary in three different ways.
   Console::WriteLine( "Initial contents of the ListDictionary:" );
   PrintKeysAndValues( myCol );
   
   // Deletes a key.
   myCol->Remove( "Gala Apples" );
   Console::WriteLine( "The collection contains the following elements after removing \"Gala Apples\":" );
   PrintKeysAndValues( myCol );
   
   // Clears the entire collection.
   myCol->Clear();
   Console::WriteLine( "The collection contains the following elements after it is cleared:" );
   PrintKeysAndValues( myCol );
}

/*
This code produces the following output.

Initial contents of the ListDictionary:
   KEY                       VALUE
   Braeburn Apples           1.49
   Fuji Apples               1.29
   Gala Apples               1.49
   Golden Delicious Apples   1.29
   Granny Smith Apples       0.89
   Red Delicious Apples      0.99

The collection contains the following elements after removing "Gala Apples":
   KEY                       VALUE
   Braeburn Apples           1.49
   Fuji Apples               1.29
   Golden Delicious Apples   1.29
   Granny Smith Apples       0.89
   Red Delicious Apples      0.99

The collection contains the following elements after it is cleared:
   KEY                       VALUE

*/

using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesListDictionary  {

   public static void Main()  {

      // Creates and initializes a new ListDictionary.
      ListDictionary myCol = new ListDictionary();
      myCol.Add( "Braeburn Apples", "1.49" );
      myCol.Add( "Fuji Apples", "1.29" );
      myCol.Add( "Gala Apples", "1.49" );
      myCol.Add( "Golden Delicious Apples", "1.29" );
      myCol.Add( "Granny Smith Apples", "0.89" );
      myCol.Add( "Red Delicious Apples", "0.99" );

      // Displays the values in the ListDictionary in three different ways.
      Console.WriteLine( "Initial contents of the ListDictionary:" );
      PrintKeysAndValues( myCol );

      // Deletes a key.
      myCol.Remove( "Gala Apples" );
      Console.WriteLine( "The collection contains the following elements after removing \"Gala Apples\":" );
      PrintKeysAndValues( myCol );

      // Clears the entire collection.
      myCol.Clear();
      Console.WriteLine( "The collection contains the following elements after it is cleared:" );
      PrintKeysAndValues( myCol );
   }

   public static void PrintKeysAndValues( IDictionary myCol )  {
      Console.WriteLine( "   KEY                       VALUE" );
      foreach ( DictionaryEntry de in myCol )
         Console.WriteLine( "   {0,-25} {1}", de.Key, de.Value );
      Console.WriteLine();
   }
}


/*
This code produces the following output.

Initial contents of the ListDictionary:
   KEY                       VALUE
   Braeburn Apples           1.49
   Fuji Apples               1.29
   Gala Apples               1.49
   Golden Delicious Apples   1.29
   Granny Smith Apples       0.89
   Red Delicious Apples      0.99

The collection contains the following elements after removing "Gala Apples":
   KEY                       VALUE
   Braeburn Apples           1.49
   Fuji Apples               1.29
   Golden Delicious Apples   1.29
   Granny Smith Apples       0.89
   Red Delicious Apples      0.99

The collection contains the following elements after it is cleared:
   KEY                       VALUE

*/

Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesListDictionary   

   Public Shared Sub Main()

      ' Creates and initializes a new ListDictionary.
      Dim myCol As New ListDictionary()
      myCol.Add("Braeburn Apples", "1.49")
      myCol.Add("Fuji Apples", "1.29")
      myCol.Add("Gala Apples", "1.49")
      myCol.Add("Golden Delicious Apples", "1.29")
      myCol.Add("Granny Smith Apples", "0.89")
      myCol.Add("Red Delicious Apples", "0.99")

      ' Displays the values in the ListDictionary in three different ways.
      Console.WriteLine("Initial contents of the ListDictionary:")
      PrintKeysAndValues(myCol)

      ' Deletes a key.
      myCol.Remove("Gala Apples")
      Console.WriteLine("The collection contains the following elements after removing ""Gala Apples"":")
      PrintKeysAndValues(myCol)

      ' Clears the entire collection.
      myCol.Clear()
      Console.WriteLine("The collection contains the following elements after it is cleared:")
      PrintKeysAndValues(myCol)

   End Sub

   Public Shared Sub PrintKeysAndValues(myCol As IDictionary)

      Console.WriteLine("   KEY                       VALUE")
      Dim de As DictionaryEntry
      For Each de In  myCol
         Console.WriteLine("   {0,-25} {1}", de.Key, de.Value)
      Next de
      Console.WriteLine()

   End Sub

End Class


'This code produces the following output.
'
'Initial contents of the ListDictionary:
'   KEY                       VALUE
'   Braeburn Apples           1.49
'   Fuji Apples               1.29
'   Gala Apples               1.49
'   Golden Delicious Apples   1.29
'   Granny Smith Apples       0.89
'   Red Delicious Apples      0.99
'
'The collection contains the following elements after removing "Gala Apples":
'   KEY                       VALUE
'   Braeburn Apples           1.49
'   Fuji Apples               1.29
'   Golden Delicious Apples   1.29
'   Granny Smith Apples       0.89
'   Red Delicious Apples      0.99
'
'The collection contains the following elements after it is cleared:
'   KEY                       VALUE
'

Keterangan

Objek yang tidak memiliki korelasi antara statusnya dan nilai kode hashnya biasanya tidak boleh digunakan sebagai kunci. Misalnya, objek String lebih baik daripada objek StringBuilder untuk digunakan sebagai kunci.

Anda juga dapat menggunakan Item[] properti untuk menambahkan elemen baru dengan mengatur nilai kunci yang tidak ada di ListDictionary; misalnya, myCollection["myNonexistentKey"] = myValue. Namun, jika kunci yang ditentukan sudah ada di ListDictionary, pengaturan Item[] properti akan menimpa nilai lama. Sebaliknya, Add metode tidak memodifikasi elemen yang ada.

Metode ini adalah operasi O(n), di mana n adalah Count.

Berlaku untuk

Lihat juga