Bindable CheckedListBox

public partial class Form1 : Form
{
    /// <summary>
    /// Just something to put in the list.
    /// It can be anything you like.
    /// </summary>
    class Fruit
    {
        protected string _name;
 
        public Fruit(string name)
        {
            _name = name;
        }
 
        public string Name
        {
            get { return _name; }
        }
    }
 
    /// <summary>
    /// The list of objects to be used as a data source.
    /// We use a 'BindingList' so 'item changed' events are fired
    /// when we update the data source. This will cause the 
    /// GUI to refresh automatically when we change the data source.
    /// This is classic MVC in action.
    /// </summary>
    private BindingList<fruit> _fruitsDs = new BindingList<fruit>();
 
    public Form1()
    {
        InitializeComponent();
 
        // Add some items to the data source.
        _fruitsDs.Add(new Fruit("apple"));
        _fruitsDs.Add(new Fruit("grapes"));
        _fruitsDs.Add(new Fruit("pear"));
        
        // Binding 'trick'.
        ListBox fruitListAsListBox = (ListBox)_fruitList;
        fruitListAsListBox.DataSource = _fruitsDs;
        fruitListAsListBox.DisplayMember = "Name";                   
    }
 
    private void button1_Click(object sender, EventArgs e)
    {
        // Change the list after we set up the binding.
        // If the data source was a simple 'List', this wouldn't
        // have caused the GUI to refresh.
        _fruitsDs.Add(new Fruit("banana"));
    }
}
</fruit></fruit>

private BindingList<Fruit> _fruitsDs = new BindingList<Fruit>();

Imports System.ComponentModel
Imports System.Drawing.Design
 
Public Class ExCheckedListBox
    Inherits CheckedListBox
 
    Private _value As Integer
 
    Public Property Value() As Integer
        Get
            Try
                Dim poweredNumber As Integer = 1
                For i As Integer = 0 To Me.Items.Count - 1
                    If Me.GetItemChecked(i) Then
                        Me._value = Me._value Or poweredNumber
                    ElseIf Me._value And poweredNumber <> 0 Then
                        Me._value -= poweredNumber
                    End If
                    poweredNumber *= 2
                Next
            Catch ex1 As ArgumentException
                Throw ex1
            Catch ex As Exception
                Throw ex
            End Try
            Return Me._value
        End Get
        Set(ByVal value As Integer)
            Me._value = value
            Try
                Dim poweredNumber As Integer = 1
                For i As Integer = 0 To Me.Items.Count - 1
                    If Me._value And poweredNumber <> 0 Then
                        Me.SetItemCheckState(i, CheckState.Checked)
                    Else
                        Me.SetItemCheckState(i, CheckState.Unchecked)
                    End If
                    poweredNumber *= 2
                Next
            Catch ex1 As ArgumentException
                Throw ex1
            Catch ex As Exception
                Throw ex
            End Try
        End Set
    End Property
 
    ''' <summary>
    ''' Gets or sets the data source for this CustomControls.CheckedListBox.
    ''' 
    ''' Exceptions:
    '''   System.ArgumentException:
    '''     The assigned value does not implement the System.Collections.IList or
    '''     System.ComponentModel.IListSource intefaces.
    ''' </summary>
    ''' <returns>
    ''' An object that implements the System.Collections.IList or
    ''' System.ComponentModel.IListSource interfaces, such as a 
    ''' System.Data.DataSet or an System.Array. The default is null.
    ''' </returns>
    <DefaultValue(""), AttributeProvider(GetType(IListSource)), RefreshProperties(RefreshProperties.All), Browsable(True)> _
    Public Shadows Property DataSource() As Object
        Get
            Return MyBase.DataSource
        End Get
        Set(ByVal value As Object)
            MyBase.DataSource = value
        End Set
    End Property
 
    ''' <summary>
    ''' Gets or sets the property to display for this
    ''' CustomControls.CheckedListBox
    ''' </summary>
    ''' <returns>
    ''' A System.String specifying the name of the object property that is
    ''' contained in the collection specified by the
    ''' CustomControls.CheckedListBox.DataSource property. The default is
    ''' an empty string ("").
    ''' </returns>
    <DefaultValue(""), _
     TypeConverter("System.Windows.Forms.Design.DataMemberFieldConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"), _
     Editor("System.Windows.Forms.Design.DataMemberFieldEditor, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", GetType(UITypeEditor)), _
     Browsable(True)> _
    Public Shadows Property DisplayMember() As String
        Get
            Return MyBase.DisplayMember
        End Get
        Set(ByVal value As String)
            MyBase.DisplayMember = value
        End Set
    End Property
 
    <DefaultValue(""), _
     TypeConverter("System.Windows.Forms.Design.DataMemberFieldConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"), _
     Editor("System.Windows.Forms.Design.DataMemberFieldEditor, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", GetType(UITypeEditor)), _
     Browsable(True)> _
    Public Shadows Property ValueMember() As String
        Get
            Return MyBase.ValueMember
        End Get
        Set(ByVal value As String)
            MyBase.ValueMember = value
        End Set
    End Property
 
    <Browsable(False)> _
    Public ReadOnly Property SelectedValues() As Array
        Get
            Dim i As Integer = -1
            Dim ret() As Object = Nothing
            For Each idx As Integer In Me.SelectedIndices
                i += 1
                ReDim Preserve ret(i)
                ret(i) = CType(MyBase.DataManager.List.Item(idx), DataRowView).Item(Me.ValueMember)
            Next
            Return ret
        End Get
    End Property
 
    <Browsable(False)> _
    Public ReadOnly Property CheckedValues() As Array
        Get
            Dim i As Integer = -1
            Dim ret() As Object = Nothing
            For Each idx As Integer In Me.CheckedIndices
                i += 1
                ReDim Preserve ret(i)
                ret(i) = CType(MyBase.DataManager.List.Item(idx), DataRowView).Item(Me.ValueMember)
            Next
            Return ret
        End Get
    End Property
 
End Class