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Collection(Of T).Remove Method

Removes the first occurrence of a specific object from the Collection(Of T).

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

Public Function Remove ( _
	item As T _
) As Boolean
Dim instance As Collection 
Dim item As T
Dim returnValue As Boolean 

returnValue = instance.Remove(item)


Type: T

The object to remove from the Collection(Of T). The value can be Nothing for reference types.

Return Value

Type: System.Boolean
true if item is successfully removed; otherwise, false. This method also returns false if item was not found in the original Collection(Of T).


ICollection(Of T).Remove(T)

This method determines equality using the default equality comparer EqualityComparer(Of T).Default for T, the type of values in the list.

This method performs a linear search; therefore, the average execution time is proportional to Count. That is, this method is an O(n) operation, where n is Count.

Notes to Inheritors:

Derived classes can override RemoveItem to change the behavior of this method.

The following code example demonstrates many of the properties and methods of Collection(Of T). The code example creates a collection of strings, uses the Add method to add several strings, displays the Count, and lists the strings. The example uses the IndexOf method to find the index of a string and the Contains method to determine whether a string is in the collection. The example inserts a string using the Insert method and retrieves and sets strings using the default Item property (the indexer in C#). The example removes strings by string identity using the Remove method and by index using the RemoveAt method. Finally, the Clear method is used to clear all strings from the collection.

Imports System
Imports System.Collections.Generic
Imports System.Collections.ObjectModel

Public Class Demo

    Public Shared Sub Main() 

        Dim dinosaurs As New Collection(Of String)


        Console.WriteLine("{0} dinosaurs:", dinosaurs.Count)

        Console.WriteLine(vbLf & "IndexOf(""Muttaburrasaurus""): {0}", _

        Console.WriteLine(vbLf & "Contains(""Caudipteryx""): {0}", _

        Console.WriteLine(vbLf & "Insert(2, ""Nanotyrannus"")")
        dinosaurs.Insert(2, "Nanotyrannus")

        Console.WriteLine(vbLf & "dinosaurs(2): {0}", dinosaurs(2))

        Console.WriteLine(vbLf & "dinosaurs(2) = ""Microraptor""")
        dinosaurs(2) = "Microraptor"

        Console.WriteLine(vbLf & "Remove(""Microraptor"")")

        Console.WriteLine(vbLf & "RemoveAt(0)")

        Console.WriteLine(vbLf & "dinosaurs.Clear()")
        Console.WriteLine("Count: {0}", dinosaurs.Count)

    End Sub 

    Private Shared Sub Display(ByVal cs As Collection(Of String)) 
        For Each item As String In cs
        Next item
    End Sub 
End Class 

' This code example produces the following output: 

'4 dinosaurs: 


'IndexOf("Muttaburrasaurus"): 3 

'Contains("Caudipteryx"): True 

'Insert(2, "Nanotyrannus") 


'dinosaurs(2): Nanotyrannus 

'dinosaurs(2) = "Microraptor" 






'Count: 0

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