Dictionary<TKey, TValue>.ICollection<KeyValuePair<TKey, TValue>>.CopyTo Method

  • Article

Copies the elements of the ICollection<T> to an array of type KeyValuePair<TKey, TValue>, starting at the specified array index.

Namespace:  System.Collections.Generic
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
Private Sub CopyTo ( _
    array As KeyValuePair(Of TKey, TValue)(), _
    index As Integer _
) Implements ICollection(Of KeyValuePair(Of TKey, TValue)).CopyTo
'Usage
Dim instance As Dictionary
Dim array As KeyValuePair(Of TKey, TValue)()
Dim index As Integer

CType(instance, ICollection(Of KeyValuePair(Of TKey, TValue))).CopyTo(array, _
    index)

void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(
    KeyValuePair<TKey, TValue>[] array,
    int index
)

private:
virtual void CopyTo(
    array<KeyValuePair<TKey, TValue>>^ array, 
    int index
) sealed = ICollection<KeyValuePair<TKey, TValue>>::CopyTo

J# supports the use of explicit interface implementations, but not the declaration of new ones.

JScript does not support explicit interface implementations.

Parameters

  • index
    Type: System.Int32

    The zero-based index in array at which copying begins.

Implements

ICollection<T>.CopyTo(array<T[], Int32)

Exceptions

Exception Condition
ArgumentNullException

array is nulla null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException

index is less than 0.
ArgumentException

index is equal to or greater than the length of array.

-or-

The number of elements in the source ICollection<T> is greater than the available space from index to the end of the destination array.

Remarks

This method is an O(n) operation, where n is Count.

Examples

The following code example shows how to use the The following code example shows how to use the ICollection<KeyValuePair<TKey, TValue>>.Add, ICollection<KeyValuePair<TKey, TValue>>.Contains, ICollection<KeyValuePair<TKey, TValue>>.CopyTo, and ICollection<KeyValuePair<TKey, TValue>>.Remove methods of the System.Collections.Generic.ICollection<T> generic interface to manipulate a Dictionary<TKey, TValue> object.

Imports System
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main() 

        ' Create a new dictionary of strings, with string keys, and
        ' access it through the generic ICollection interface. The
        ' generic ICollection interface views the dictionary as a
        ' collection of KeyValuePair objects with the same type
        ' arguments as the dictionary.
        '
        Dim openWith As ICollection(Of KeyValuePair(Of String, String)) _
            = New Dictionary(Of String, String)

        ' Add some elements to the dictionary. When elements are 
        ' added through the ICollection(Of T) interface, the keys
        ' and values must be wrapped in KeyValuePair objects.
        '
        openWith.Add(New KeyValuePair(Of String,String)("txt", "notepad.exe"))
        openWith.Add(New KeyValuePair(Of String,String)("bmp", "paint.exe"))
        openWith.Add(New KeyValuePair(Of String,String)("dib", "paint.exe"))
        openWith.Add(New KeyValuePair(Of String,String)("rtf", "wordpad.exe"))

        Console.WriteLine()
        For Each element As KeyValuePair(Of String, String) in openWith
            Console.WriteLine("{0}, {1}", element.Key, element.Value)
        Next

        ' The Contains method also takes a KeyValuePair object.
        '
        Console.WriteLine(vbLf & _
            "Contains(KeyValuePair(""txt"", ""notepad.exe"")): {0}", _
            openWith.Contains(New KeyValuePair(Of String,String)("txt", "notepad.exe")))

        ' The Remove method takes a KeyValuePair object.)
        '
        ' Use the Remove method to remove a key/value pair.
        Console.WriteLine(vbLf &  _
            "Remove(New KeyValuePair(""dib"", ""paint.exe""))")
        openWith.Remove(New KeyValuePair(Of String,String)("dib", "paint.exe"))

        Console.WriteLine()
        For Each element As KeyValuePair(Of String, String) in openWith
            Console.WriteLine("{0}, {1}", element.Key, element.Value)
        Next

        ' Create an array of KeyValuePair objects and copy the 
        ' contents of the dictionary to it. Subtract one from the
        ' array size because Visual Basic allocates an extra array
        ' element.
        Dim copy(openWith.Count - 1) As KeyValuePair(Of String, String)
        openWith.CopyTo(copy, 0)

        ' List the contents of the array.
        '
        Console.WriteLine()
        For Each element As KeyValuePair(Of String, String) in copy
            Console.WriteLine("{0}, {1}", element.Key, element.Value)
        Next

    End Sub

End Class

' This code example produces the following output:
'
'txt, notepad.exe
'bmp, paint.exe
'dib, paint.exe
'rtf, wordpad.exe
'
'Contains(KeyValuePair("txt", "notepad.exe")): True
'
'Remove(New KeyValuePair("dib", "paint.exe"))
'
'txt, notepad.exe
'bmp, paint.exe
'rtf, wordpad.exe
'
'txt, notepad.exe
'bmp, paint.exe
'rtf, wordpad.exe 

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new dictionary of strings, with string keys, and
        // access it through the generic ICollection interface. The
        // generic ICollection interface views the dictionary as a
        // collection of KeyValuePair objects with the same type
        // arguments as the dictionary.
        //
        ICollection<KeyValuePair<String, String>> openWith =
            new Dictionary<String, String>();

        // Add some elements to the dictionary. When elements are 
        // added through the ICollection<T> interface, the keys
        // and values must be wrapped in KeyValuePair objects.
        //
        openWith.Add(new KeyValuePair<String,String>("txt", "notepad.exe"));
        openWith.Add(new KeyValuePair<String,String>("bmp", "paint.exe"));
        openWith.Add(new KeyValuePair<String,String>("dib", "paint.exe"));
        openWith.Add(new KeyValuePair<String,String>("rtf", "wordpad.exe"));

        Console.WriteLine();
        foreach( KeyValuePair<string, string> element in openWith )
        {
            Console.WriteLine("{0}, {1}", element.Key, element.Value);
        }

        // The Contains method also takes a KeyValuePair object.
        //
        Console.WriteLine(
            "\nContains(KeyValuePair(\"txt\", \"notepad.exe\")): {0}", 
            openWith.Contains(new KeyValuePair<String,String>("txt", "notepad.exe")));

        // The Remove method takes a KeyValuePair object.)
        //
        // Use the Remove method to remove a key/value pair.
        Console.WriteLine("\nRemove(new KeyValuePair(\"dib\", \"paint.exe\"))");
        openWith.Remove(new KeyValuePair<String,String>("dib", "paint.exe"));

        Console.WriteLine();
        foreach( KeyValuePair<string, string> element in openWith )
        {
            Console.WriteLine("{0}, {1}", element.Key, element.Value);
        }

        // Create an array of KeyValuePair objects and copy the 
        // contents of the dictionary to it. 
        // 
        KeyValuePair<string, string>[] copy = 
            new KeyValuePair<string, string>[openWith.Count];
        openWith.CopyTo(copy, 0);

        // List the contents of the array.
        //
        Console.WriteLine();
        foreach( KeyValuePair<string, string> element in copy )
        {
            Console.WriteLine("{0}, {1}", element.Key, element.Value);
        }
    }
}

/* This code example produces the following output:

txt, notepad.exe
bmp, paint.exe
dib, paint.exe
rtf, wordpad.exe

Contains(KeyValuePair("txt", "notepad.exe")): True

Remove(new KeyValuePair("dib", "paint.exe"))

txt, notepad.exe
bmp, paint.exe
rtf, wordpad.exe

txt, notepad.exe
bmp, paint.exe
rtf, wordpad.exe
 */

Platforms

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0 SP1, 3.0, 2.0 SP1, 2.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 1.0

See Also

Reference

Dictionary<TKey, TValue> Class

Dictionary<TKey, TValue> Members

System.Collections.Generic Namespace