IListSource Interface
Collapse the table of content
Expand the table of content

IListSource Interface


Provides functionality to an object to return a list that can be bound to a data source.

Namespace:   System.ComponentModel
Assembly:  System (in System.dll)

<TypeConverterAttribute("System.Windows.Forms.Design.DataSourceConverter, System.Design, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>
Public Interface IListSource


Gets a value indicating whether the collection is a collection of IList objects.


Returns an IList that can be bound to a data source from an object that does not implement an IList itself.

You typically use this interface to return a list that can be bound to a data source, from an object that does not implement IList itself.

Binding to data can occur at either run time or in a designer, but there are rules for each. At run time, you can bind to data in any of the following:

  • Array

  • Implementer of IList, provided the implementer has a strongly typed Item property (that is, the Type is anything but Object). You can accomplish this by making the default implementation of Item private. If you want to create an IList that follows the rules of a strongly typed collection, you should derive from CollectionBase.

  • Implementer of ITypedList.

In a designer, you can initialize binding to Component objects by following the same rules.


Implementers of IListSource can return an IList that contains a collection of IList objects.

The following code example demonstrates how to implement the IListSource interface. A component named EmployeeListSource exposes an IList for data binding by implementing the GetList method. For a full code listing, see How to: Implement the IListSource Interface.

Imports System.ComponentModel

Public Class EmployeeListSource
    Inherits Component
    Implements IListSource

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

        'Required for Windows.Forms Class Composition Designer support

    End Sub

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

        'This call is required by the Component Designer.

    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
        End If
    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
            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("Vereb�lyi, �gnes", 15700000))
        End If

        Return ble

    End Function

#End Region

End Class

.NET Framework
Available since 1.1
Return to top
© 2015 Microsoft