IListSource Interface

Definição

public interface class IListSource

public interface IListSource

[System.ComponentModel.TypeConverter("System.Windows.Forms.Design.DataSourceConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public interface IListSource

[System.ComponentModel.TypeConverter("System.Windows.Forms.Design.DataSourceConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public interface IListSource

type IListSource = interface

[<System.ComponentModel.TypeConverter("System.Windows.Forms.Design.DataSourceConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
type IListSource = interface

[<System.ComponentModel.TypeConverter("System.Windows.Forms.Design.DataSourceConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
type IListSource = interface

Public Interface IListSource

Derivado

System.Data.DataSet

System.Data.DataTable

System.Data.Linq.EntitySet<TEntity>

System.Data.Linq.Table<TEntity>

System.Data.Objects.DataClasses.EntityCollection<TEntity>

Mais…

Atributos

TypeConverterAttribute

Exemplos

O exemplo de código a seguir demonstra como implementar o IListSource interface. Um componente denominado EmployeeListSource expõe um IList for data binding ao implementar o GetList método. Para uma lista completa de código, veja Como: Implementar a Interface IListSource.

using System.ComponentModel;

namespace IListSourceCS;

public class EmployeeListSource : Component, IListSource
{
    public EmployeeListSource() { }

    public EmployeeListSource(IContainer container) => container.Add(this);

    #region IListSource Members

    bool IListSource.ContainsListCollection => false;

    System.Collections.IList IListSource.GetList()
    {
        BindingList<Employee> ble = DesignMode
        ? []
        : [
            new("Aaberg, Jesper", 26000000),
            new ("Aaberg, Jesper", 26000000),
            new ("Cajhen, Janko", 19600000),
            new ("Furse, Kari", 19000000),
            new ("Langhorn, Carl", 16000000),
            new ("Todorov, Teodor", 15700000),
            new ("Verebélyi, Ágnes", 15700000)
            ];

        return ble;
    }

    #endregion
}

Imports System.ComponentModel

Public Class EmployeeListSource
    Inherits Component
    Implements IListSource

    <System.Diagnostics.DebuggerNonUserCode()> _
Public Sub New(ByVal Container As System.ComponentModel.IContainer)
        MyClass.New()

        'Required for Windows.Forms Class Composition Designer support
        Container.Add(Me)

    End Sub

    <System.Diagnostics.DebuggerNonUserCode()> _
    Public Sub New()
        MyBase.New()

        'This call is required by the Component Designer.
        InitializeComponent()

    End Sub

    'Component overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Component Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Component Designer
    'It can be modified using the Component Designer.
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        components = New System.ComponentModel.Container()
    End Sub

#Region "IListSource Members"

    Public ReadOnly Property ContainsListCollection() As Boolean Implements System.ComponentModel.IListSource.ContainsListCollection
        Get
            Return False
        End Get
    End Property

    Public Function GetList() As System.Collections.IList Implements System.ComponentModel.IListSource.GetList

        Dim ble As New BindingList(Of Employee)

        If Not Me.DesignMode Then
            ble.Add(New Employee("Aaberg, Jesper", 26000000))
            ble.Add(New Employee("Cajhen, Janko", 19600000))
            ble.Add(New Employee("Furse, Kari", 19000000))
            ble.Add(New Employee("Langhorn, Carl", 16000000))
            ble.Add(New Employee("Todorov, Teodor", 15700000))
            ble.Add(New Employee("Verebélyi, Ágnes", 15700000))
        End If

        Return ble

    End Function

#End Region

End Class

Observações

Normalmente utiliza-se esta interface para devolver uma lista que pode ser associada a uma fonte de dados, a partir de um objeto que não se implementa IList a si próprio.

A ligação a dados pode ocorrer em tempo de execução ou num designer, mas existem regras para cada um. Em tempo de execução, pode vincular dados em qualquer uma das seguintes opções:

• Array

• Implementador de IList, desde que o implementador tenha uma propriedade fortemente tipada Item[] (ou seja, o Type é qualquer coisa menos Object). Pode conseguir isto tornando a implementação padrão de Item[] privada. Se quiser criar um IList que siga as regras de uma coleção fortemente tipada, deve derivar de CollectionBase.

• Implementador de ITypedList.

Num designer, podes inicializar a ligação a Component objetos seguindo as mesmas regras.

Ver também

• IListSource
• ITypedList
• BindingList<T>
• IBindingList
• CollectionBase
• Vinculação de Dados e Windows Forms