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ITypedList Interface

  • Reference

Definition

Namespace:
System.ComponentModel
Assembly:
System.ComponentModel.TypeConverter.dll
Assembly:
System.dll
Assembly:
netstandard.dll
Package:
System.ComponentModel.TypeConverter v4.3.0

Provides functionality to discover the schema for a bindable list, where the properties available for binding differ from the public properties of the object to bind to.

public interface class ITypedList
public interface ITypedList
type ITypedList = interface
Public Interface ITypedList
Derived

Examples

The following code example demonstrates how to implement the ITypedList interface. A generic type named SortableBindingList derives from the BindingList<T> class and implements the ITypedList interface. For a full code listing, see How to: Implement the ITypedList Interface.

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Windows.Forms;
using System.Collections;
using System.Reflection;

namespace ITypedListCS
{
    [Serializable()]
    public class SortableBindingList<T> : BindingList<T>, ITypedList
    {
        [NonSerialized()]
        private PropertyDescriptorCollection properties;

        public SortableBindingList() : base()
        {
            // Get the 'shape' of the list. 
            // Only get the public properties marked with Browsable = true.
            PropertyDescriptorCollection pdc = TypeDescriptor.GetProperties(
                typeof(T), 
                new Attribute[] { new BrowsableAttribute(true) });

            // Sort the properties.
            properties = pdc.Sort();
        }

        #region ITypedList Implementation

        public PropertyDescriptorCollection GetItemProperties(PropertyDescriptor[] listAccessors)
        {
            PropertyDescriptorCollection pdc;

            if (listAccessors!=null && listAccessors.Length>0)
            {
                // Return child list shape.
                pdc = ListBindingHelper.GetListItemProperties(listAccessors[0].PropertyType);
            }
            else
            {
                // Return properties in sort order.
                pdc = properties;
            }

            return pdc;
        }

        // This method is only used in the design-time framework 
        // and by the obsolete DataGrid control.
        public string GetListName(PropertyDescriptor[] listAccessors)
        {   
            return typeof(T).Name;
        }

        #endregion
    }
}

Imports System.ComponentModel
Imports System.Collections.Generic
Imports System.Windows.Forms

<Serializable()> _
Public Class SortableBindingList(Of Tkey)
    Inherits BindingList(Of Tkey)
    Implements ITypedList

    <NonSerialized()> _
    Private properties As PropertyDescriptorCollection

    Public Sub New()
        MyBase.New()

        ' Get the 'shape' of the list. 
        ' Only get the public properties marked with Browsable = true.
        Dim pdc As PropertyDescriptorCollection = TypeDescriptor.GetProperties(GetType(Tkey), New Attribute() {New BrowsableAttribute(True)})

        ' Sort the properties.
        properties = pdc.Sort()

    End Sub

#Region "ITypedList Implementation"

    Public Function GetItemProperties(ByVal listAccessors() As System.ComponentModel.PropertyDescriptor) As System.ComponentModel.PropertyDescriptorCollection Implements System.ComponentModel.ITypedList.GetItemProperties

        Dim pdc As PropertyDescriptorCollection

        If (Not (listAccessors Is Nothing)) And (listAccessors.Length > 0) Then
            ' Return child list shape
            pdc = ListBindingHelper.GetListItemProperties(listAccessors(0).PropertyType)
        Else
            ' Return properties in sort order
            pdc = properties
        End If

        Return pdc

    End Function

    ' This method is only used in the design-time framework 
    ' and by the obsolete DataGrid control.
    Public Function GetListName( _
    ByVal listAccessors() As PropertyDescriptor) As String _
    Implements System.ComponentModel.ITypedList.GetListName

        Return GetType(Tkey).Name

    End Function

#End Region

End Class

Remarks

Use this interface if, for instance, you are using a DataView object that represents a customer table, you want to bind to the properties on the customer object that the DataView represents, not the properties of the DataView.

This interface is not required for design-time support of a bindable list.

Binding to data can occur either at run time or in a designer, but there are rules for both. 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.

For more information on binding to a data source, see the System.Windows.Forms.Binding class.

Methods

GetItemProperties(PropertyDescriptor[])

Returns the PropertyDescriptorCollection that represents the properties on each item used to bind data.
GetListName(PropertyDescriptor[])

Returns the name of the list.

Applies to

See also