CollectionBase Classe

Definição

public ref class CollectionBase abstract : System::Collections::IList

public abstract class CollectionBase : System.Collections.IList

[System.Serializable]
public abstract class CollectionBase : System.Collections.IList

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class CollectionBase : System.Collections.IList

type CollectionBase = class
    interface ICollection
    interface IEnumerable
    interface IList

[<System.Serializable>]
type CollectionBase = class
    interface IList
    interface ICollection
    interface IEnumerable

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type CollectionBase = class
    interface IList
    interface ICollection
    interface IEnumerable

Public MustInherit Class CollectionBase
Implements IList

Herança

Object

CollectionBase

Derivado

System.CodeDom.CodeAttributeArgumentCollection

System.CodeDom.CodeAttributeDeclarationCollection

System.CodeDom.CodeCatchClauseCollection

System.CodeDom.CodeCommentStatementCollection

System.CodeDom.CodeDirectiveCollection

Mais…

Atributos

SerializableAttribute ComVisibleAttribute

Implementações

ICollection IEnumerable IList

Exemplos

O exemplo de código a seguir implementa a CollectionBase classe e usa essa implementação para criar uma coleção de Int16 objetos.

#using <System.dll>

using namespace System;
using namespace System::Collections;

public ref class Int16Collection: public CollectionBase
{
public:

   property Int16 Item [int]
   {
      Int16 get( int index )
      {
         return ( (Int16)(List[ index ]));
      }

      void set( int index, Int16 value )
      {
         List[ index ] = value;
      }
   }
   int Add( Int16 value )
   {
      return (List->Add( value ));
   }

   int IndexOf( Int16 value )
   {
      return (List->IndexOf( value ));
   }

   void Insert( int index, Int16 value )
   {
      List->Insert( index, value );
   }

   void Remove( Int16 value )
   {
      List->Remove( value );
   }

   bool Contains( Int16 value )
   {
      // If value is not of type Int16, this will return false.
      return (List->Contains( value ));
   }

protected:
   virtual void OnInsert( int /*index*/, Object^ /*value*/ ) override
   {
      // Insert additional code to be run only when inserting values.
   }

   virtual void OnRemove( int /*index*/, Object^ /*value*/ ) override
   {
      // Insert additional code to be run only when removing values.
   }

   virtual void OnSet( int /*index*/, Object^ /*oldValue*/, Object^ /*newValue*/ ) override
   {
      // Insert additional code to be run only when setting values.
   }

   virtual void OnValidate( Object^ value ) override
   {
      if ( value->GetType() != Type::GetType( "System.Int16" ) )
            throw gcnew ArgumentException( "value must be of type Int16.","value" );
   }

};

void PrintIndexAndValues( Int16Collection^ myCol );
void PrintValues2( Int16Collection^ myCol );
int main()
{
   // Create and initialize a new CollectionBase.
   Int16Collection^ myI16 = gcnew Int16Collection;
   
   // Add elements to the collection.
   myI16->Add( (Int16)1 );
   myI16->Add( (Int16)2 );
   myI16->Add( (Int16)3 );
   myI16->Add( (Int16)5 );
   myI16->Add( (Int16)7 );

   // Display the contents of the collection using the enumerator.
   Console::WriteLine( "Contents of the collection (using enumerator):" );
   PrintValues2( myI16 );

   // Display the contents of the collection using the Count property and the Item property.
   Console::WriteLine( "Initial contents of the collection (using Count and Item):" );
   PrintIndexAndValues( myI16 );

   // Search the collection with Contains and IndexOf.
   Console::WriteLine( "Contains 3: {0}", myI16->Contains( 3 ) );
   Console::WriteLine( "2 is at index {0}.", myI16->IndexOf( 2 ) );
   Console::WriteLine();

   // Insert an element into the collection at index 3.
   myI16->Insert( 3, (Int16)13 );
   Console::WriteLine( "Contents of the collection after inserting at index 3:" );
   PrintIndexAndValues( myI16 );

   // Get and set an element using the index.
   myI16->Item[ 4 ] = 123;
   Console::WriteLine( "Contents of the collection after setting the element at index 4 to 123:" );
   PrintIndexAndValues( myI16 );

   // Remove an element from the collection.
   myI16->Remove( (Int16)2 );

   // Display the contents of the collection using the Count property and the Item property.
   Console::WriteLine( "Contents of the collection after removing the element 2:" );
   PrintIndexAndValues( myI16 );
}

// Uses the Count property and the Item property.
void PrintIndexAndValues( Int16Collection^ myCol )
{
   for ( int i = 0; i < myCol->Count; i++ )
      Console::WriteLine( "   [{0}]:   {1}", i, myCol->Item[ i ] );
   Console::WriteLine();
}

// Uses the enumerator. 
void PrintValues2( Int16Collection^ myCol )
{
   System::Collections::IEnumerator^ myEnumerator = myCol->GetEnumerator();
   while ( myEnumerator->MoveNext() )
      Console::WriteLine( "   {0}", myEnumerator->Current );

   Console::WriteLine();
}

/* 
This code produces the following output.

Contents of the collection (using enumerator):
   1
   2
   3
   5
   7

Initial contents of the collection (using Count and Item):
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   5
   [4]:   7

Contains 3: True
2 is at index 1.

Contents of the collection after inserting at index 3:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   5
   [5]:   7

Contents of the collection after setting the element at index 4 to 123:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   123
   [5]:   7

Contents of the collection after removing the element 2:
   [0]:   1
   [1]:   3
   [2]:   13
   [3]:   123
   [4]:   7

*/

using System;
using System.Collections;

public class Int16Collection : CollectionBase  {

   public Int16 this[ int index ]  {
      get  {
         return( (Int16) List[index] );
      }
      set  {
         List[index] = value;
      }
   }

   public int Add( Int16 value )  {
      return( List.Add( value ) );
   }

   public int IndexOf( Int16 value )  {
      return( List.IndexOf( value ) );
   }

   public void Insert( int index, Int16 value )  {
      List.Insert( index, value );
   }

   public void Remove( Int16 value )  {
      List.Remove( value );
   }

   public bool Contains( Int16 value )  {
      // If value is not of type Int16, this will return false.
      return( List.Contains( value ) );
   }

   protected override void OnInsert( int index, Object value )  {
      // Insert additional code to be run only when inserting values.
   }

   protected override void OnRemove( int index, Object value )  {
      // Insert additional code to be run only when removing values.
   }

   protected override void OnSet( int index, Object oldValue, Object newValue )  {
      // Insert additional code to be run only when setting values.
   }

   protected override void OnValidate( Object value )  {
      if ( value.GetType() != typeof(System.Int16) )
         throw new ArgumentException( "value must be of type Int16.", "value" );
   }
}

public class SamplesCollectionBase  {

   public static void Main()  {

      // Create and initialize a new CollectionBase.
      Int16Collection myI16 = new Int16Collection();

      // Add elements to the collection.
      myI16.Add( (Int16) 1 );
      myI16.Add( (Int16) 2 );
      myI16.Add( (Int16) 3 );
      myI16.Add( (Int16) 5 );
      myI16.Add( (Int16) 7 );

      // Display the contents of the collection using foreach. This is the preferred method.
      Console.WriteLine( "Contents of the collection (using foreach):" );
      PrintValues1( myI16 );

      // Display the contents of the collection using the enumerator.
      Console.WriteLine( "Contents of the collection (using enumerator):" );
      PrintValues2( myI16 );

      // Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine( "Initial contents of the collection (using Count and Item):" );
      PrintIndexAndValues( myI16 );

      // Search the collection with Contains and IndexOf.
      Console.WriteLine( "Contains 3: {0}", myI16.Contains( 3 ) );
      Console.WriteLine( "2 is at index {0}.", myI16.IndexOf( 2 ) );
      Console.WriteLine();

      // Insert an element into the collection at index 3.
      myI16.Insert( 3, (Int16) 13 );
      Console.WriteLine( "Contents of the collection after inserting at index 3:" );
      PrintIndexAndValues( myI16 );

      // Get and set an element using the index.
      myI16[4] = 123;
      Console.WriteLine( "Contents of the collection after setting the element at index 4 to 123:" );
      PrintIndexAndValues( myI16 );

      // Remove an element from the collection.
      myI16.Remove( (Int16) 2 );

      // Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine( "Contents of the collection after removing the element 2:" );
      PrintIndexAndValues( myI16 );
   }

   // Uses the Count property and the Item property.
   public static void PrintIndexAndValues( Int16Collection myCol )  {
      for ( int i = 0; i < myCol.Count; i++ )
         Console.WriteLine( "   [{0}]:   {1}", i, myCol[i] );
      Console.WriteLine();
   }

   // Uses the foreach statement which hides the complexity of the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintValues1( Int16Collection myCol )  {
      foreach ( Int16 i16 in myCol )
         Console.WriteLine( "   {0}", i16 );
      Console.WriteLine();
   }

   // Uses the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintValues2( Int16Collection myCol )  {
      System.Collections.IEnumerator myEnumerator = myCol.GetEnumerator();
      while ( myEnumerator.MoveNext() )
         Console.WriteLine( "   {0}", myEnumerator.Current );
      Console.WriteLine();
   }
}


/*
This code produces the following output.

Contents of the collection (using foreach):
   1
   2
   3
   5
   7

Contents of the collection (using enumerator):
   1
   2
   3
   5
   7

Initial contents of the collection (using Count and Item):
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   5
   [4]:   7

Contains 3: True
2 is at index 1.

Contents of the collection after inserting at index 3:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   5
   [5]:   7

Contents of the collection after setting the element at index 4 to 123:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   123
   [5]:   7

Contents of the collection after removing the element 2:
   [0]:   1
   [1]:   3
   [2]:   13
   [3]:   123
   [4]:   7

*/

Imports System.Collections


Public Class Int16Collection
   Inherits CollectionBase


   Default Public Property Item(index As Integer) As Int16
      Get
         Return CType(List(index), Int16)
      End Get
      Set
         List(index) = value
      End Set
   End Property


   Public Function Add(value As Int16) As Integer
      Return List.Add(value)
   End Function 'Add

   Public Function IndexOf(value As Int16) As Integer
      Return List.IndexOf(value)
   End Function 'IndexOf


   Public Sub Insert(index As Integer, value As Int16)
      List.Insert(index, value)
   End Sub


   Public Sub Remove(value As Int16)
      List.Remove(value)
   End Sub


   Public Function Contains(value As Int16) As Boolean
      ' If value is not of type Int16, this will return false.
      Return List.Contains(value)
   End Function 'Contains


   Protected Overrides Sub OnInsert(index As Integer, value As Object)
      ' Insert additional code to be run only when inserting values.
   End Sub


   Protected Overrides Sub OnRemove(index As Integer, value As Object)
      ' Insert additional code to be run only when removing values.
   End Sub


   Protected Overrides Sub OnSet(index As Integer, oldValue As Object, newValue As Object)
      ' Insert additional code to be run only when setting values.
   End Sub


   Protected Overrides Sub OnValidate(value As Object)
      If Not GetType(System.Int16).IsAssignableFrom(value.GetType()) Then
         Throw New ArgumentException("value must be of type Int16.", "value")
      End If
   End Sub

End Class


Public Class SamplesCollectionBase

   Public Shared Sub Main()

      ' Creates and initializes a new CollectionBase.
      Dim myI16 As New Int16Collection()

      ' Adds elements to the collection.
      myI16.Add( 1 )
      myI16.Add( 2 )
      myI16.Add( 3 )
      myI16.Add( 5 )
      myI16.Add( 7 )

      ' Display the contents of the collection using For Each. This is the preferred method.
      Console.WriteLine("Contents of the collection (using For Each):")
      PrintValues1(myI16)
      
      ' Display the contents of the collection using the enumerator.
      Console.WriteLine("Contents of the collection (using enumerator):")
      PrintValues2(myI16)
      
      ' Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine("Initial contents of the collection (using Count and Item):")
      PrintIndexAndValues(myI16)
      
      ' Searches the collection with Contains and IndexOf.
      Console.WriteLine("Contains 3: {0}", myI16.Contains(3))
      Console.WriteLine("2 is at index {0}.", myI16.IndexOf(2))
      Console.WriteLine()
      
      ' Inserts an element into the collection at index 3.
      myI16.Insert(3, 13)
      Console.WriteLine("Contents of the collection after inserting at index 3:")
      PrintIndexAndValues(myI16)
      
      ' Gets and sets an element using the index.
      myI16(4) = 123
      Console.WriteLine("Contents of the collection after setting the element at index 4 to 123:")
      PrintIndexAndValues(myI16)
      
      ' Removes an element from the collection.
      myI16.Remove(2)

      ' Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine("Contents of the collection after removing the element 2:")
      PrintIndexAndValues(myI16)

    End Sub


    ' Uses the Count property and the Item property.
    Public Shared Sub PrintIndexAndValues(myCol As Int16Collection)
      Dim i As Integer
      For i = 0 To myCol.Count - 1
          Console.WriteLine("   [{0}]:   {1}", i, myCol(i))
      Next i
      Console.WriteLine()
    End Sub


    ' Uses the For Each statement which hides the complexity of the enumerator.
    ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
    Public Shared Sub PrintValues1(myCol As Int16Collection)
      Dim i16 As Int16
      For Each i16 In  myCol
          Console.WriteLine("   {0}", i16)
      Next i16
      Console.WriteLine()
    End Sub


    ' Uses the enumerator. 
    ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
    Public Shared Sub PrintValues2(myCol As Int16Collection)
      Dim myEnumerator As System.Collections.IEnumerator = myCol.GetEnumerator()
      While myEnumerator.MoveNext()
          Console.WriteLine("   {0}", myEnumerator.Current)
      End While
      Console.WriteLine()
    End Sub

End Class


'This code produces the following output.
'
'Contents of the collection (using For Each):
'   1
'   2
'   3
'   5
'   7
'
'Contents of the collection (using enumerator):
'   1
'   2
'   3
'   5
'   7
'
'Initial contents of the collection (using Count and Item):
'   [0]:   1
'   [1]:   2
'   [2]:   3
'   [3]:   5
'   [4]:   7
'
'Contains 3: True
'2 is at index 1.
'
'Contents of the collection after inserting at index 3:
'   [0]:   1
'   [1]:   2
'   [2]:   3
'   [3]:   13
'   [4]:   5
'   [5]:   7
'
'Contents of the collection after setting the element at index 4 to 123:
'   [0]:   1
'   [1]:   2
'   [2]:   3
'   [3]:   13
'   [4]:   123
'   [5]:   7
'
'Contents of the collection after removing the element 2:
'   [0]:   1
'   [1]:   3
'   [2]:   13
'   [3]:   123
'   [4]:   7

Comentários

Uma CollectionBase instância é sempre modificável. Consulte ReadOnlyCollectionBase para obter uma versão somente leitura dessa classe.

A capacidade de um CollectionBase é o número de elementos que o CollectionBase pode conter. À medida que os elementos são adicionados a um CollectionBase, a capacidade é automaticamente aumentada conforme necessário por meio da realocação. A capacidade pode ser reduzida definindo a Capacity propriedade explicitamente.

Notas aos Implementadores

Essa classe base é fornecida para facilitar a criação de uma coleção personalizada fortemente tipada para os implementadores. Os implementadores são incentivados a estender essa classe base em vez de criar suas próprias.

Construtores

Propriedades

Métodos

Implantações explícitas de interface

Métodos de Extensão

Aplica-se a

Acesso thread-safe

Os membros estáticos públicos (Shared no Visual Basic) desse são thread-safe. Não há garantia de que qualquer membro de instância seja seguro para threads.

Essa implementação não fornece um wrapper sincronizado (thread safe) para um CollectionBase, mas as classes derivadas podem criar suas próprias versões sincronizadas do CollectionBase usando a SyncRoot propriedade .

A enumeração por meio de uma coleção não é intrinsecamente um procedimento seguro de thread. Mesmo quando uma coleção está sincronizada, outros threads ainda podem modificar a coleção, o que faz o enumerador lançar uma exceção. Para garantir thread-safe durante a enumeração, é possível bloquear a coleção durante toda a enumeração ou verificar as exceções resultantes das alterações feitas por outros threads.

Confira também

• ArrayList
• IList
• ReadOnlyCollectionBase
• System.Collections.Generic
• Executando operações de cadeia de caracteres que não levam em conta a cultura