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Dictionary(Of TKey, TValue).ICollection(Of KeyValuePair(Of TKey, TValue)).Remove Method

Removes a key and value from the dictionary.

Namespace:  System.Collections.Generic
Assembly:  mscorlib (in mscorlib.dll)
'Declaration
Private Function Remove ( _
	keyValuePair As KeyValuePair(Of TKey, TValue) _
) As Boolean Implements ICollection(Of KeyValuePair(Of TKey, TValue)).Remove
'Usage
Dim instance As Dictionary 
Dim keyValuePair As KeyValuePair(Of TKey, TValue)
Dim returnValue As Boolean 

returnValue = CType(instance, ICollection(Of KeyValuePair(Of TKey, TValue))).Remove(keyValuePair)

Parameters

keyValuePair
Type: System.Collections.Generic.KeyValuePair(Of TKey, TValue)

The KeyValuePair(Of TKey, TValue) structure representing the key and value to remove from the Dictionary(Of TKey, TValue).

Return Value

Type: System.Boolean
true if the key and value represented by keyValuePair is successfully found and removed; otherwise, false. This method returns false if keyValuePair is not found in the ICollection(Of T).

Implements

ICollection(Of T).Remove(T)

This method uses Comparer to determine equality for the key, and the default equality comparer EqualityComparer(Of T).Default to determine equality for the value.

This method approaches an O(1) operation.

The following code example shows how to use the System#Collections#Generic#ICollection{System#Collections#Generic#KeyValuePair{`0,`1}}#Add(KeyValuePairTKey, TValue), System#Collections#Generic#ICollection{System#Collections#Generic#KeyValuePair{`0,`1}}#Contains(KeyValuePairTKey, TValue), System#Collections#Generic#ICollection{System#Collections#Generic#KeyValuePair{`0,`1}}#CopyTo(KeyValuePairTKey, TValue, Int32), and System#Collections#Generic#ICollection{System#Collections#Generic#KeyValuePair{`0,`1}}#Remove(KeyValuePairTKey, TValue) methods of the System.Collections.Generic.ICollection(Of T) generic interface to manipulate a Dictionary(Of 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 

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, 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, Zune

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.

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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