
Provides a generic collection that supports data binding.
Assembly: System (in System.dll)
'Declaration <SerializableAttribute> _ <HostProtectionAttribute(SecurityAction.LinkDemand, SharedState := True)> _ Public Class BindingList(Of T) _ Inherits Collection(Of T) _ Implements IBindingList, IList, ICollection, IEnumerable, _ ICancelAddNew, IRaiseItemChangedEvents
Type Parameters
- T
The type of elements in the list.
The BindingList(Of T) class can be used as a base class to create a two-way data-binding mechanism. BindingList(Of T) provides a concrete, generic implementation of the IBindingList interface. This is an alternative to implementing the complete IBindingList interface, which can be difficult because of the subtle interaction between IBindingList, IEditableObject, and the associated CurrencyManager. However, the typical solutions programmer will use a class that provides data binding functionality, such as BindingSource, instead of directly using BindingList(Of T).
BindingList(Of T) supports factory-created instances through the extensible AddNew method. (This same type of extensibility is also found in other classes, such as BindingSource) In addition, since this class implements the ICancelAddNew interface, it enables transactional commits or rollbacks of the new item through the EndNew and CancelNew methods.
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The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
The following code example demonstrates binding to a BindingList(Of T) component containing a business object. This is a complete example that contains a Main method.
Option Explicit On Option Strict On Imports System Imports System.Collections.Generic Imports System.ComponentModel Imports System.Drawing Imports System.Text Imports System.Windows.Forms Class Form1 Inherits Form Private textBox2 As TextBox Private listBox1 As ListBox Private WithEvents button1 As Button Private textBox1 As TextBox Private randomNumber As New Random() Public Sub New() Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font Me.textBox1 = New System.Windows.Forms.TextBox() Me.textBox2 = New System.Windows.Forms.TextBox() Me.listBox1 = New System.Windows.Forms.ListBox() Me.button1 = New System.Windows.Forms.Button() Me.textBox1.Location = New System.Drawing.Point(169, 26) Me.textBox1.Size = New System.Drawing.Size(100, 20) Me.textBox1.Text = "Bracket" Me.textBox2.Location = New System.Drawing.Point(169, 57) Me.textBox2.ReadOnly = True Me.textBox2.Size = New System.Drawing.Size(100, 20) Me.textBox2.Text = "4343" Me.listBox1.FormattingEnabled = True Me.listBox1.Location = New System.Drawing.Point(12, 12) Me.listBox1.Size = New System.Drawing.Size(120, 95) Me.button1.Location = New System.Drawing.Point(180, 83) Me.button1.Size = New System.Drawing.Size(75, 23) Me.button1.Text = "Add New Item" Me.ClientSize = New System.Drawing.Size(292, 266) Me.Controls.Add(Me.button1) Me.Controls.Add(Me.listBox1) Me.Controls.Add(Me.textBox2) Me.Controls.Add(Me.textBox1) Me.Text = "Parts Form" AddHandler Me.Load, AddressOf Form1_Load End Sub 'New Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) InitializeListOfParts() listBox1.DataSource = listOfParts listBox1.DisplayMember = "PartName" End Sub ' Declare a new BindingListOfT with the Part business object. Private WithEvents listOfParts As BindingList(Of Part) Private Sub InitializeListOfParts() ' Create the new BindingList of Part type. listOfParts = New BindingList(Of Part) ' Allow new parts to be added, but not removed once committed. listOfParts.AllowNew = True listOfParts.AllowRemove = False ' Raise ListChanged events when new parts are added. listOfParts.RaiseListChangedEvents = True ' Do not allow parts to be edited. listOfParts.AllowEdit = False ' Add a couple of parts to the list. listOfParts.Add(New Part("Widget", 1234)) listOfParts.Add(New Part("Gadget", 5647)) End Sub ' Create a new part from the text in the two text boxes. Private Sub listOfParts_AddingNew(ByVal sender As Object, _ ByVal e As AddingNewEventArgs) Handles listOfParts.AddingNew e.NewObject = New Part(textBox1.Text, Integer.Parse(textBox2.Text)) End Sub ' Add the new part unless the part number contains ' spaces. In that case cancel the add. Private Sub button1_Click(ByVal sender As Object, _ ByVal e As EventArgs) Handles button1.Click Dim newPart As Part = listOfParts.AddNew() If newPart.PartName.Contains(" ") Then MessageBox.Show("Part names cannot contain spaces.") listOfParts.CancelNew(listOfParts.IndexOf(newPart)) Else textBox2.Text = randomNumber.Next(9999).ToString() textBox1.Text = "Enter part name" End If End Sub <STAThread()> _ Shared Sub Main() Application.EnableVisualStyles() Application.Run(New Form1()) End Sub End Class ' A simple business object for example purposes. Public Class Part Private name As String Private number As Integer Public Sub New() End Sub Public Sub New(ByVal nameForPart As String, _ ByVal numberForPart As Integer) PartName = nameForPart PartNumber = numberForPart End Sub Public Property PartName() As String Get Return name End Get Set(ByVal value As String) name = Value End Set End Property Public Property PartNumber() As Integer Get Return number End Get Set(ByVal value As Integer) number = Value End Set End Property End Class
System.Collections.ObjectModel.Collection(Of T)
System.ComponentModel.BindingList(Of T)
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role not supported), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.