Collection<T>.Remove(T) Método

Definição

Remove a primeira ocorrência de um objeto específico do Collection<T>.Removes the first occurrence of a specific object from the Collection<T>.

public:
 virtual bool Remove(T item);
public bool Remove (T item);
abstract member Remove : 'T -> bool
override this.Remove : 'T -> bool
Public Function Remove (item As T) As Boolean

Parâmetros

item
T

O objeto a remover do Collection<T>.The object to remove from the Collection<T>. O valor pode ser null para tipos de referência.The value can be null for reference types.

Retornos

true se item for removido com êxito; caso contrário, false.true if item is successfully removed; otherwise, false. Esse método também retornará false se item não tiver sido encontrado no Collection<T> original.This method also returns false if item was not found in the original Collection<T>.

Implementações

Exemplos

O exemplo de código a seguir demonstra muitas das propriedades e métodos Collection<T>do.The following code example demonstrates many of the properties and methods of Collection<T>. O exemplo de código cria uma coleção de cadeias de Add caracteres, usa o método para adicionar várias Countcadeias de caracteres, exibe o e lista as cadeias de caracteres.The code example creates a collection of strings, uses the Add method to add several strings, displays the Count, and lists the strings. O exemplo usa o IndexOf método para localizar o índice de uma cadeia de caracteres Contains e o método para determinar se uma cadeia de caracteres está na coleção.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. O exemplo insere uma cadeia de caracteres Insert usando o método e recupera e define cadeias Item[Int32] usando a propriedade padrão (o C#indexador em).The example inserts a string using the Insert method and retrieves and sets strings using the default Item[Int32] property (the indexer in C#). O exemplo remove cadeias de caracteres por identidade Remove de cadeia usando o método e RemoveAt por índice usando o método.The example removes strings by string identity using the Remove method and by index using the RemoveAt method. Por fim, Clear o método é usado para limpar todas as cadeias de caracteres da coleção.Finally, the Clear method is used to clear all strings from the collection.

using namespace System;
using namespace System::Collections::Generic;
using namespace System::Collections::ObjectModel;

public ref class Demo
{
public:
    static void Main()
    {
        Collection<String^>^ dinosaurs = gcnew Collection<String^>();

        dinosaurs->Add("Psitticosaurus");
        dinosaurs->Add("Caudipteryx");
        dinosaurs->Add("Compsognathus");
        dinosaurs->Add("Muttaburrasaurus");

        Console::WriteLine("{0} dinosaurs:", dinosaurs->Count);
        Display(dinosaurs);

        Console::WriteLine("\nIndexOf(\"Muttaburrasaurus\"): {0}",
            dinosaurs->IndexOf("Muttaburrasaurus"));

        Console::WriteLine("\nContains(\"Caudipteryx\"): {0}",
            dinosaurs->Contains("Caudipteryx"));

        Console::WriteLine("\nInsert(2, \"Nanotyrannus\")");
        dinosaurs->Insert(2, "Nanotyrannus");
        Display(dinosaurs);

        Console::WriteLine("\ndinosaurs[2]: {0}", dinosaurs[2]);

        Console::WriteLine("\ndinosaurs[2] = \"Microraptor\"");
        dinosaurs[2] = "Microraptor";
        Display(dinosaurs);

        Console::WriteLine("\nRemove(\"Microraptor\")");
        dinosaurs->Remove("Microraptor");
        Display(dinosaurs);

        Console::WriteLine("\nRemoveAt(0)");
        dinosaurs->RemoveAt(0);
        Display(dinosaurs);

        Console::WriteLine("\ndinosaurs.Clear()");
        dinosaurs->Clear();
        Console::WriteLine("Count: {0}", dinosaurs->Count);
    }

private:
    static void Display(Collection<String^>^ cs)
    {
        Console::WriteLine();
        for each( String^ item in cs )
        {
            Console::WriteLine(item);
        }
    }
};

int main()
{
    Demo::Main();
}

/* This code example produces the following output:

4 dinosaurs:

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

IndexOf("Muttaburrasaurus"): 3

Contains("Caudipteryx"): True

Insert(2, "Nanotyrannus")

Psitticosaurus
Caudipteryx
Nanotyrannus
Compsognathus
Muttaburrasaurus

dinosaurs[2]: Nanotyrannus

dinosaurs[2] = "Microraptor"

Psitticosaurus
Caudipteryx
Microraptor
Compsognathus
Muttaburrasaurus

Remove("Microraptor")

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

RemoveAt(0)

Caudipteryx
Compsognathus
Muttaburrasaurus

dinosaurs.Clear()
Count: 0
 */
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

public class Demo
{
    public static void Main()
    {
        Collection<string> dinosaurs = new Collection<string>();

        dinosaurs.Add("Psitticosaurus");
        dinosaurs.Add("Caudipteryx");
        dinosaurs.Add("Compsognathus");
        dinosaurs.Add("Muttaburrasaurus");

        Console.WriteLine("{0} dinosaurs:", dinosaurs.Count);
        Display(dinosaurs);
    
        Console.WriteLine("\nIndexOf(\"Muttaburrasaurus\"): {0}", 
            dinosaurs.IndexOf("Muttaburrasaurus"));

        Console.WriteLine("\nContains(\"Caudipteryx\"): {0}", 
            dinosaurs.Contains("Caudipteryx"));

        Console.WriteLine("\nInsert(2, \"Nanotyrannus\")");
        dinosaurs.Insert(2, "Nanotyrannus");
        Display(dinosaurs);

        Console.WriteLine("\ndinosaurs[2]: {0}", dinosaurs[2]);

        Console.WriteLine("\ndinosaurs[2] = \"Microraptor\"");
        dinosaurs[2] = "Microraptor";
        Display(dinosaurs);

        Console.WriteLine("\nRemove(\"Microraptor\")");
        dinosaurs.Remove("Microraptor");
        Display(dinosaurs);

        Console.WriteLine("\nRemoveAt(0)");
        dinosaurs.RemoveAt(0);
        Display(dinosaurs);

        Console.WriteLine("\ndinosaurs.Clear()");
        dinosaurs.Clear();
        Console.WriteLine("Count: {0}", dinosaurs.Count);
    }
    
    private static void Display(Collection<string> cs)
    {
        Console.WriteLine();
        foreach( string item in cs )
        {
            Console.WriteLine(item);
        }
    }
}

/* This code example produces the following output:

4 dinosaurs:

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

IndexOf("Muttaburrasaurus"): 3

Contains("Caudipteryx"): True

Insert(2, "Nanotyrannus")

Psitticosaurus
Caudipteryx
Nanotyrannus
Compsognathus
Muttaburrasaurus

dinosaurs[2]: Nanotyrannus

dinosaurs[2] = "Microraptor"

Psitticosaurus
Caudipteryx
Microraptor
Compsognathus
Muttaburrasaurus

Remove("Microraptor")

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

RemoveAt(0)

Caudipteryx
Compsognathus
Muttaburrasaurus

dinosaurs.Clear()
Count: 0
 */
Imports System.Collections.Generic
Imports System.Collections.ObjectModel

Public Class Demo
    
    Public Shared Sub Main() 

        Dim dinosaurs As New Collection(Of String)

        dinosaurs.Add("Psitticosaurus")
        dinosaurs.Add("Caudipteryx")
        dinosaurs.Add("Compsognathus")
        dinosaurs.Add("Muttaburrasaurus")

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

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

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

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

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

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

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

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

' This code example produces the following output:
'
'4 dinosaurs:
'
'Psitticosaurus
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'IndexOf("Muttaburrasaurus"): 3
'
'Contains("Caudipteryx"): True
'
'Insert(2, "Nanotyrannus")
'
'Psitticosaurus
'Caudipteryx
'Nanotyrannus
'Compsognathus
'Muttaburrasaurus
'
'dinosaurs(2): Nanotyrannus
'
'dinosaurs(2) = "Microraptor"
'
'Psitticosaurus
'Caudipteryx
'Microraptor
'Compsognathus
'Muttaburrasaurus
'
'Remove("Microraptor")
'
'Psitticosaurus
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'RemoveAt(0)
'
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'dinosaurs.Clear()
'Count: 0

Comentários

Esse método determina a igualdade usando o EqualityComparer<T>.Default comparador de igualdade padrão para T, o tipo de valores na lista.This method determines equality using the default equality comparer EqualityComparer<T>.Default for T, the type of values in the list.

Esse método executa uma pesquisa linear; Portanto, o tempo médio de execução é proporcional ao Count.This method performs a linear search; therefore, the average execution time is proportional to Count. Ou seja, esse método é uma operação On(), em n que Counté.That is, this method is an O(n) operation, where n is Count.

Notas aos Herdeiros

As classes derivadas podem RemoveItem(Int32) substituir para alterar o comportamento desse método.Derived classes can override RemoveItem(Int32) to change the behavior of this method.

Aplica-se a

Veja também