MSDN Library

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

Removes a key and value from the dictionary.

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

'Declaration
Private Function Remove ( _
	keyValuePair As KeyValuePair(Of TKey, TValue) _
) As Boolean Implements ICollection(Of KeyValuePair(Of TKey, TValue)).Remove

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 example shows how to use the ICollection(Of KeyValuePair(Of TKey, TValue)).Add, ICollection(Of KeyValuePair(Of TKey, TValue)).Contains, ICollection(Of KeyValuePair(Of TKey, TValue)).CopyTo, and ICollection(Of KeyValuePair(Of TKey, TValue)).Remove 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 

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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