IBindingList Interface

Definição

Fornece os recursos necessários para dar suporte a cenários complexos e simples durante a associação de uma fonte de dados.Provides the features required to support both complex and simple scenarios when binding to a data source.

public interface class IBindingList : System::Collections::IList
public interface IBindingList : System.Collections.IList
type IBindingList = interface
    interface IList
    interface ICollection
    interface IEnumerable
Public Interface IBindingList
Implements IList
Derivado
Implementações

Exemplos

O exemplo a seguir fornece uma implementação simples da IBindingList interface.The following example provides a simple implementation of the IBindingList interface. A CustomerList classe armazena as informações do cliente em uma lista.The CustomerList class stores customer information in a list. Este exemplo pressupõe que você usou a Customer classe que pode ser encontrada no exemplo IEditableObject na classe.This example assumes that you have used the Customer class that can be found in the example in the IEditableObject class.

public ref class CustomersList: public CollectionBase, public IBindingList
{
private:
   ListChangedEventArgs^ resetEvent;
   ListChangedEventHandler^ onListChanged;
   virtual event ListChangedEventHandler^ ListChanged;

public:
   property bool AllowEdit 
   {
      // Implements IBindingList.
      virtual bool get() sealed
      {
         return true;
      }
   }

   virtual property bool AllowNew 
   {
      bool get()
      {
         return true;
      }
   }

   property bool AllowRemove 
   {
      virtual bool get()
      {
         return true;
      }

   }

   property bool SupportsChangeNotification 
   {
      virtual bool get()
      {
         return true;
      }

   }

   property bool SupportsSearching 
   {
      virtual bool get()
      {
         return true;
      }

   }

   property bool SupportsSorting 
   {
      virtual bool get()
      {
         return true;
      }

   }

   // Methods.
   virtual Object^ AddNew()
   {
      Customer^ c = gcnew Customer( this->Count->ToString() );
      List->Add( c );
      return c;
   }


   property bool IsSorted 
   {

      // Unsupported properties.
      virtual bool get()
      {
         throw gcnew NotSupportedException;
         return false;
      }

   }

   property ListSortDirection SortDirection 
   {
      virtual ListSortDirection get()
      {
         throw gcnew NotSupportedException;
         return ListSortDirection::Ascending;
      }

   }

   property PropertyDescriptor^ SortProperty 
   {
      virtual PropertyDescriptor^ get()
      {
         throw gcnew NotSupportedException;
         return nullptr;
      }

   }

   // Unsupported Methods.
   virtual void AddIndex( PropertyDescriptor^ property )
   {
      throw gcnew NotSupportedException;
   }

   virtual void ApplySort( PropertyDescriptor^ property, ListSortDirection direction )
   {
      throw gcnew NotSupportedException;
   }

   virtual int Find( PropertyDescriptor^ property, Object^ key )
   {
      throw gcnew NotSupportedException;
      return 0;
   }

   virtual void RemoveIndex( PropertyDescriptor^ property )
   {
      throw gcnew NotSupportedException;
   }

   virtual void RemoveSort()
   {
      throw gcnew NotSupportedException;
   }


   // Worker functions to populate the list with data.
   static Customer^ ReadCustomer1()
   {
      Customer^ cust = gcnew Customer( "536-45-1245" );
      cust->FirstName = "Jo";
      cust->LastName = "Brown";
      return cust;
   }

   static Customer^ ReadCustomer2()
   {
      Customer^ cust = gcnew Customer( "246-12-5645" );
      cust->FirstName = "Robert";
      cust->LastName = "Brown";
      return cust;
   }

protected:
   virtual void OnListChanged( ListChangedEventArgs^ ev )
   {
      if ( onListChanged != nullptr )
      {
         onListChanged( this, ev );
      }
   }

   virtual void OnClear() override
   {
      List->Clear();
   }

   virtual void OnClearComplete() override
   {
      OnListChanged( resetEvent );
   }

   virtual void OnInsertComplete( int index, Object^ value ) override
   {
      Customer^ c = safe_cast<Customer^>(value);
      c->Parent = this;
      OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemAdded,index ) );
   }

   virtual void OnRemoveComplete( int index, Object^ value ) override
   {
      Customer^ c = safe_cast<Customer^>(value);
      c->Parent = this;
      OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemDeleted,index ) );
   }

   virtual void OnSetComplete( int index, Object^ oldValue, Object^ newValue ) override
   {
      if ( oldValue != newValue )
      {
         Customer^ oldcust = safe_cast<Customer^>(oldValue);
         Customer^ newcust = safe_cast<Customer^>(newValue);
         oldcust->Parent = 0;
         newcust->Parent = this;
         OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemAdded,index ) );
      }
   }

public:

   // Constructor
   CustomersList()
   {
      resetEvent = gcnew ListChangedEventArgs( ListChangedType::Reset,-1 );
   }

   void LoadCustomers()
   {
      IList^ l = static_cast<IList^>(this);
      l->Add( ReadCustomer1() );
      l->Add( ReadCustomer2() );
      OnListChanged( resetEvent );
   }

   property Object^ Item [int]
   {
      Object^ get( int index )
      {
         return static_cast<Customer^>(List->Item[ index ]);
      }

      void set( int index, Object^ value )
      {
         List->Item[ index ] = value;
      }

   }
   int Add( Customer^ value )
   {
      return List->Add( value );
   }

   Customer^ AddNew()
   {
      return safe_cast<Customer^>(static_cast<IBindingList^>(this)->AddNew());
   }

   void Remove( Customer^ value )
   {
      List->Remove( value );
   }

internal:

   // Called by Customer when it changes.
   void CustomerChanged( Customer^ cust )
   {
      int index = List->IndexOf( cust );
      OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemChanged,index ) );
   }

};
public class CustomersList :  CollectionBase, IBindingList
{

    private ListChangedEventArgs resetEvent = new ListChangedEventArgs(ListChangedType.Reset, -1);
    private ListChangedEventHandler onListChanged;

    public void LoadCustomers() 
    {
        IList l = (IList)this;
        l.Add(ReadCustomer1());
        l.Add(ReadCustomer2());
        OnListChanged(resetEvent);
    }

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

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

    public Customer AddNew() 
    {
        return (Customer)((IBindingList)this).AddNew();
    }

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

    
    protected virtual void OnListChanged(ListChangedEventArgs ev) 
    {
        if (onListChanged != null) 
        {
            onListChanged(this, ev);
        }
    }
    

    protected override void OnClear() 
    {
        foreach (Customer c in List) 
        {
            c.Parent = null;
        }
    }

    protected override void OnClearComplete() 
    {
        OnListChanged(resetEvent);
    }

    protected override void OnInsertComplete(int index, object value) 
    {
        Customer c = (Customer)value;
        c.Parent = this;
        OnListChanged(new ListChangedEventArgs(ListChangedType.ItemAdded, index));
    }

    protected override void OnRemoveComplete(int index, object value) 
    {
        Customer c = (Customer)value;
        c.Parent = this;
        OnListChanged(new ListChangedEventArgs(ListChangedType.ItemDeleted, index));
    }

    protected override void OnSetComplete(int index, object oldValue, object newValue) 
    {
        if (oldValue != newValue) 
        {

            Customer oldcust = (Customer)oldValue;
            Customer newcust = (Customer)newValue;
            
            oldcust.Parent = null;
            newcust.Parent = this;
            
            
            OnListChanged(new ListChangedEventArgs(ListChangedType.ItemAdded, index));
        }
    }
    
    // Called by Customer when it changes.
    internal void CustomerChanged(Customer cust) 
    {
        
        int index = List.IndexOf(cust);
        
        OnListChanged(new ListChangedEventArgs(ListChangedType.ItemChanged, index));
    }
    

    // Implements IBindingList.
    bool IBindingList.AllowEdit 
    { 
        get { return true ; }
    }

    bool IBindingList.AllowNew 
    { 
        get { return true ; }
    }

    bool IBindingList.AllowRemove 
    { 
        get { return true ; }
    }

    bool IBindingList.SupportsChangeNotification 
    { 
        get { return true ; }
    }
    
    bool IBindingList.SupportsSearching 
    { 
        get { return false ; }
    }

    bool IBindingList.SupportsSorting 
    { 
        get { return false ; }
    }


    // Events.
    public event ListChangedEventHandler ListChanged 
    {
        add 
        {
            onListChanged += value;
        }
        remove 
        {
            onListChanged -= value;
        }
    }

    // Methods.
    object IBindingList.AddNew() 
    {
        Customer c = new Customer(this.Count.ToString());
        List.Add(c);
        return c;
    }


    // Unsupported properties.
    bool IBindingList.IsSorted 
    { 
        get { throw new NotSupportedException(); }
    }

    ListSortDirection IBindingList.SortDirection 
    { 
        get { throw new NotSupportedException(); }
    }


    PropertyDescriptor IBindingList.SortProperty 
    { 
        get { throw new NotSupportedException(); }
    }


    // Unsupported Methods.
    void IBindingList.AddIndex(PropertyDescriptor property) 
    {
        throw new NotSupportedException(); 
    }

    void IBindingList.ApplySort(PropertyDescriptor property, ListSortDirection direction) 
    {
        throw new NotSupportedException(); 
    }

    int IBindingList.Find(PropertyDescriptor property, object key) 
    {
        throw new NotSupportedException(); 
    }

    void IBindingList.RemoveIndex(PropertyDescriptor property) 
    {
        throw new NotSupportedException(); 
    }

    void IBindingList.RemoveSort() 
    {
        throw new NotSupportedException(); 
    }

    // Worker functions to populate the list with data.
    private static Customer ReadCustomer1() 
    {
        Customer cust = new Customer("536-45-1245");
        cust.FirstName = "Jo";
        cust.LastName = "Brown";
        return cust;
    }
    
    private static Customer ReadCustomer2() 
    {
        Customer cust = new Customer("246-12-5645");
        cust.FirstName = "Robert";
        cust.LastName = "Brown";
        return cust;
    }
}

Public Class CustomersList
    Inherits CollectionBase
    Implements IBindingList 

    Private resetEvent As New ListChangedEventArgs(ListChangedType.Reset, -1)
    Private onListChanged1 As ListChangedEventHandler


    Public Sub LoadCustomers()
        Dim l As IList = CType(Me, IList)
        l.Add(ReadCustomer1())
        l.Add(ReadCustomer2())
        OnListChanged(resetEvent)
    End Sub 


    Default Public Property Item(ByVal index As Integer) As Customer
        Get
            Return CType(List(index), Customer)
        End Get
        Set(ByVal Value As Customer)
            List(index) = Value
        End Set
    End Property


    Public Function Add(ByVal value As Customer) As Integer
        Return List.Add(value)
    End Function 


    Public Function AddNew2() As Customer
        Return CType(CType(Me, IBindingList).AddNew(), Customer)
    End Function 


    Public Sub Remove(ByVal value As Customer)
        List.Remove(value)
    End Sub 



    Protected Overridable Sub OnListChanged(ByVal ev As ListChangedEventArgs)
        If (onListChanged1 IsNot Nothing) Then
            onListChanged1(Me, ev)
        End If
    End Sub 



    Protected Overrides Sub OnClear()
        Dim c As Customer
        For Each c In List
            c.parent = Nothing
        Next c
    End Sub 


    Protected Overrides Sub OnClearComplete()
        OnListChanged(resetEvent)
    End Sub 


    Protected Overrides Sub OnInsertComplete(ByVal index As Integer, ByVal value As Object)
        Dim c As Customer = CType(value, Customer)
        c.parent = Me
        OnListChanged(New ListChangedEventArgs(ListChangedType.ItemAdded, index))
    End Sub 


    Protected Overrides Sub OnRemoveComplete(ByVal index As Integer, ByVal value As Object)
        Dim c As Customer = CType(value, Customer)
        c.parent = Me
        OnListChanged(New ListChangedEventArgs(ListChangedType.ItemDeleted, index))
    End Sub 


    Protected Overrides Sub OnSetComplete(ByVal index As Integer, ByVal oldValue As Object, ByVal newValue As Object)
        If oldValue <> newValue Then

            Dim oldcust As Customer = CType(oldValue, Customer)
            Dim newcust As Customer = CType(newValue, Customer)

            oldcust.parent = Nothing
            newcust.parent = Me

            OnListChanged(New ListChangedEventArgs(ListChangedType.ItemAdded, index))
        End If
    End Sub 


    ' Called by Customer when it changes.
    Friend Sub CustomerChanged(ByVal cust As Customer)
        Dim index As Integer = List.IndexOf(cust)
        OnListChanged(New ListChangedEventArgs(ListChangedType.ItemChanged, index))
    End Sub 


    ' Implements IBindingList.

    ReadOnly Property AllowEdit() As Boolean Implements IBindingList.AllowEdit
        Get
            Return True
        End Get
    End Property

    ReadOnly Property AllowNew() As Boolean Implements IBindingList.AllowNew
        Get
            Return True
        End Get
    End Property

    ReadOnly Property AllowRemove() As Boolean Implements IBindingList.AllowRemove
        Get
            Return True
        End Get
    End Property

    ReadOnly Property SupportsChangeNotification() As Boolean Implements IBindingList.SupportsChangeNotification
        Get
            Return True
        End Get
    End Property

    ReadOnly Property SupportsSearching() As Boolean Implements IBindingList.SupportsSearching
        Get
            Return False
        End Get
    End Property

    ReadOnly Property SupportsSorting() As Boolean Implements IBindingList.SupportsSorting
        Get
            Return False
        End Get
    End Property

    ' Events.
    Public Event ListChanged As ListChangedEventHandler Implements IBindingList.ListChanged


    ' Methods.
    Function AddNew() As Object Implements IBindingList.AddNew
        Dim c As New Customer(Me.Count.ToString())
        List.Add(c)
        Return c
    End Function 


    ' Unsupported properties.

    ReadOnly Property IsSorted() As Boolean Implements IBindingList.IsSorted
        Get
            Throw New NotSupportedException()
        End Get
    End Property

    ReadOnly Property SortDirection() As ListSortDirection Implements IBindingList.SortDirection
        Get
            Throw New NotSupportedException()
        End Get
    End Property


    ReadOnly Property SortProperty() As PropertyDescriptor Implements IBindingList.SortProperty
        Get
            Throw New NotSupportedException()
        End Get
    End Property


    ' Unsupported Methods.
    Sub AddIndex(ByVal prop As PropertyDescriptor) Implements IBindingList.AddIndex
        Throw New NotSupportedException()
    End Sub 


    Sub ApplySort(ByVal prop As PropertyDescriptor, ByVal direction As ListSortDirection) Implements IBindingList.ApplySort
        Throw New NotSupportedException()
    End Sub 


    Function Find(ByVal prop As PropertyDescriptor, ByVal key As Object) As Integer Implements IBindingList.Find
        Throw New NotSupportedException()
    End Function 


    Sub RemoveIndex(ByVal prop As PropertyDescriptor) Implements IBindingList.RemoveIndex
        Throw New NotSupportedException()
    End Sub 


    Sub RemoveSort() Implements IBindingList.RemoveSort
        Throw New NotSupportedException()
    End Sub 


    ' Worker functions to populate the list with data.
    Private Shared Function ReadCustomer1() As Customer
        Dim cust As New Customer("536-45-1245")
        cust.FirstName = "Jo"
        cust.LastName = "Brown"
        Return cust
    End Function 


    Private Shared Function ReadCustomer2() As Customer
        Dim cust As New Customer("246-12-5645")
        cust.FirstName = "Robert"
        cust.LastName = "Brown"
        Return cust
    End Function 
End Class

Comentários

Essa interface é implementada pela DataView classe.This interface is implemented by the DataView class. A implementação de um método deve exibir o mesmo comportamento que a implementação desse método na DataView classe.Implementation of a method should exhibit the same behavior as the implementation of that method in the DataView class.

Ao chamar os ApplySort métodos ou RemoveSort , você deve gerar um ListChanged evento com a Reset enumeração.When you call the ApplySort or RemoveSort methods, you should raise a ListChanged event with the Reset enumeration.

Ao chamar o AddNew método, você deve gerar um ListChanged evento com a ItemAdded enumeração que está carregando o índice apropriado.When you call the AddNew method, you should raise a ListChanged event with the ItemAdded enumeration carrying the appropriate index. A linha adicionada está em um estado em que pressionar ESC em um DataGridView controle pode remover a nova linha.The added row is in a state where pressing the ESC on a DataGridView control can remove the new row. Gerar o ListChanged evento com a ItemAdded enumeração uma segunda vez nessa linha indica que o item agora é uma linha que não está no estado "New".Raising the ListChanged event with the ItemAdded enumeration a second time on this row indicates that the item is now a row not in the "new" state.

Quando você remove um item ou chama o CancelEdit método em uma nova linha (se essa linha implementa IEditableObject), você deve gerar um ListChanged evento com a ItemDeleted enumeração que possui o índice apropriado.When you remove an item or call the CancelEdit method on a new row (if that row implements IEditableObject), you should raise a ListChanged event with the ItemDeleted enumeration carrying the appropriate index.

Propriedades

AllowEdit

Obtém se você pode atualizar itens na lista.Gets whether you can update items in the list.

AllowNew

Especifica se é possível adicionar itens à lista usando AddNew().Gets whether you can add items to the list using AddNew().

AllowRemove

Obtém se você pode remover os itens da lista, usando Remove(Object) ou RemoveAt(Int32).Gets whether you can remove items from the list, using Remove(Object) or RemoveAt(Int32).

Count

Obtém o número de elementos contidos no ICollection.Gets the number of elements contained in the ICollection.

(Herdado de ICollection)
IsFixedSize

Obtém um valor que indica se o IList tem um tamanho fixo.Gets a value indicating whether the IList has a fixed size.

(Herdado de IList)
IsReadOnly

Obtém um valor que indica se o IList é somente leitura.Gets a value indicating whether the IList is read-only.

(Herdado de IList)
IsSorted

Especifica se os itens na lista são classificados.Gets whether the items in the list are sorted.

IsSynchronized

Obtém um valor que indica se o acesso à ICollection é sincronizado (thread-safe).Gets a value indicating whether access to the ICollection is synchronized (thread safe).

(Herdado de ICollection)
Item[Int32]

Obtém ou define o elemento no índice especificado.Gets or sets the element at the specified index.

(Herdado de IList)
SortDirection

Obtém a direção da classificação.Gets the direction of the sort.

SortProperty

Obtém o PropertyDescriptor que está sendo usado para classificação.Gets the PropertyDescriptor that is being used for sorting.

SupportsChangeNotification

Especifica se um evento ListChanged é acionado quando a lista ou um item na lista é alterado.Gets whether a ListChanged event is raised when the list changes or an item in the list changes.

SupportsSearching

Obtém se a lista é compatível com pesquisa usando o método Find(PropertyDescriptor, Object).Gets whether the list supports searching using the Find(PropertyDescriptor, Object) method.

SupportsSorting

Obtém se a lista é compatível com classificação.Gets whether the list supports sorting.

SyncRoot

Obtém um objeto que pode ser usado para sincronizar o acesso ao ICollection.Gets an object that can be used to synchronize access to the ICollection.

(Herdado de ICollection)

Métodos

Add(Object)

Adiciona um item ao IList.Adds an item to the IList.

(Herdado de IList)
AddIndex(PropertyDescriptor)

Adiciona o PropertyDescriptor aos índices usados para pesquisa.Adds the PropertyDescriptor to the indexes used for searching.

AddNew()

Adiciona um novo item à lista.Adds a new item to the list.

ApplySort(PropertyDescriptor, ListSortDirection)

Classifica a lista com base em um PropertyDescriptor e um ListSortDirection.Sorts the list based on a PropertyDescriptor and a ListSortDirection.

Clear()

Remove todos os itens do IList.Removes all items from the IList.

(Herdado de IList)
Contains(Object)

Determinará se o IList contiver um valor específico.Determines whether the IList contains a specific value.

(Herdado de IList)
CopyTo(Array, Int32)

Copia os elementos do ICollection para um Array, começando em um determinado índice Array.Copies the elements of the ICollection to an Array, starting at a particular Array index.

(Herdado de ICollection)
Find(PropertyDescriptor, Object)

Retorna o índice da linha que tem o PropertyDescriptor determinado.Returns the index of the row that has the given PropertyDescriptor.

GetEnumerator()

Retorna um enumerador que itera em uma coleção.Returns an enumerator that iterates through a collection.

(Herdado de IEnumerable)
IndexOf(Object)

Determina o índice de um item específico em IList.Determines the index of a specific item in the IList.

(Herdado de IList)
Insert(Int32, Object)

Insere um item na IList no índice especificado.Inserts an item to the IList at the specified index.

(Herdado de IList)
Remove(Object)

Remove a primeira ocorrência de um objeto específico do IList.Removes the first occurrence of a specific object from the IList.

(Herdado de IList)
RemoveAt(Int32)

Remove o item IList no índice especificado.Removes the IList item at the specified index.

(Herdado de IList)
RemoveIndex(PropertyDescriptor)

Remove o PropertyDescriptor dos índices usados para pesquisa.Removes the PropertyDescriptor from the indexes used for searching.

RemoveSort()

Remove qualquer classificação aplicada usando ApplySort(PropertyDescriptor, ListSortDirection).Removes any sort applied using ApplySort(PropertyDescriptor, ListSortDirection).

Eventos

ListChanged

Ocorre quando a lista ou um item na lista é alterado.Occurs when the list changes or an item in the list changes.

Métodos de Extensão

Cast<TResult>(IEnumerable)

Converte os elementos de um IEnumerable para o tipo especificado.Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable)

Filtra os elementos de um IEnumerable com base em um tipo especificado.Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable)

Habilita a paralelização de uma consulta.Enables parallelization of a query.

AsQueryable(IEnumerable)

Converte um IEnumerable em um IQueryable.Converts an IEnumerable to an IQueryable.

Aplica-se a