更新:2007 年 11 月
命名空间:
System.ComponentModel 程序集:
System(在 System.dll 中)
<SerializableAttribute> _
<HostProtectionAttribute(SecurityAction.LinkDemand, SharedState := True)> _
Public Class BindingList(Of T) _
Inherits Collection(Of T) _
Implements IBindingList, IList, ICollection, IEnumerable, _
ICancelAddNew, IRaiseItemChangedEvents
Dim instance As BindingList(Of T)
[SerializableAttribute]
[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public class BindingList<T> : Collection<T>,
IBindingList, IList, ICollection, IEnumerable, ICancelAddNew,
IRaiseItemChangedEvents
[SerializableAttribute]
[HostProtectionAttribute(SecurityAction::LinkDemand, SharedState = true)]
generic<typename T>
public ref class BindingList : public Collection<T>,
IBindingList, IList, ICollection, IEnumerable, ICancelAddNew,
IRaiseItemChangedEvents
J# 支持使用泛型 API,但是不支持新泛型 API 的声明。
BindingList<(Of <(T>)>) 类可以用作创建双向数据绑定机制的基类。BindingList<(Of <(T>)>) 提供 IBindingList 接口的具体泛型实现。这样就不必实现完整的 IBindingList 接口,实现完整接口可能会因 IBindingList、IEditableObject 和关联的 CurrencyManager 之间微妙的交互而变得比较困难。不过,典型的解决方案程序员将使用提供数据绑定功能的类(如 BindingSource),而不是直接使用 BindingList<(Of <(T>)>)。
BindingList<(Of <(T>)>) 通过可扩展的 AddNew 方法支持工厂创建的实例。(在 BindingSource 等其他类中也存在这种类型的扩展性)此外,由于此类实现 ICancelAddNew 接口,因此它通过 EndNew 和 CancelNew 方法实现新项的事务性提交或回滚。
下面的代码示例演示如何绑定到一个包含业务对象的 BindingList<(Of <(T>)>) 组件。这是包含 Main 方法的完整示例。
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
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace BindingListOfTExamples
{
public partial class Form1 : Form
{
private TextBox textBox2;
private ListBox listBox1;
private Button button1;
private TextBox textBox1;
Random randomNumber = new Random();
public Form1()
{
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.textBox1 = new System.Windows.Forms.TextBox();
this.textBox2 = new System.Windows.Forms.TextBox();
this.listBox1 = new System.Windows.Forms.ListBox();
this.button1 = new System.Windows.Forms.Button();
this.textBox1.Location = new System.Drawing.Point(169, 26);
this.textBox1.Size = new System.Drawing.Size(100, 20);
this.textBox1.Text = "Bracket";
this.textBox2.Location = new System.Drawing.Point(169, 57);
this.textBox2.ReadOnly = true;
this.textBox2.Size = new System.Drawing.Size(100, 20);
this.textBox2.Text = "4343";
this.listBox1.FormattingEnabled = true;
this.listBox1.Location = new System.Drawing.Point(12, 12);
this.listBox1.Size = new System.Drawing.Size(120, 95);
this.button1.Location = new System.Drawing.Point(180, 83);
this.button1.Size = new System.Drawing.Size(75, 23);
this.button1.Text = "Add New Item";
this.button1.Click += new System.EventHandler(this.button1_Click);
this.ClientSize = new System.Drawing.Size(292, 266);
this.Controls.Add(this.button1);
this.Controls.Add(this.listBox1);
this.Controls.Add(this.textBox2);
this.Controls.Add(this.textBox1);
this.Text = "Parts Form";
this.Load += new EventHandler(Form1_Load);
}
void Form1_Load(object sender, EventArgs e)
{
InitializeListOfParts();
listBox1.DataSource = listOfParts;
listBox1.DisplayMember = "PartName";
listOfParts.AddingNew += new AddingNewEventHandler(listOfParts_AddingNew);
listOfParts.ListChanged += new ListChangedEventHandler(listOfParts_ListChanged);
}
// Declare a new BindingListOfT with the Part business object.
BindingList<Part> listOfParts;
private void InitializeListOfParts()
{
// Create the new BindingList of Part type.
listOfParts = new BindingList<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));
}
// Create a new part from the text in the two text boxes.
void listOfParts_AddingNew(object sender, AddingNewEventArgs e)
{
e.NewObject = new Part(textBox1.Text, int.Parse(textBox2.Text));
}
// Add the new part unless the part number contains
// spaces. In that case cancel the add.
private void button1_Click(object sender, EventArgs e)
{
Part newPart = listOfParts.AddNew();
if (newPart.PartName.Contains(" "))
{
MessageBox.Show("Part names cannot contain spaces.");
listOfParts.CancelNew(listOfParts.IndexOf(newPart));
}
else
{
textBox2.Text = randomNumber.Next(9999).ToString();
textBox1.Text = "Enter part name";
}
}
void listOfParts_ListChanged(object sender, ListChangedEventArgs e)
{
MessageBox.Show(e.ListChangedType.ToString());
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
// A simple business object for example purposes.
public class Part
{
private string name;
private int number;
public Part() { }
public Part(string nameForPart, int numberForPart)
{
PartName = nameForPart;
PartNumber = numberForPart;
}
public string PartName
{
get { return name; }
set { name = value; }
}
public int PartNumber
{
get { return number; }
set { number = value; }
}
}
}
System..::.Object
System.Collections.ObjectModel..::.Collection<(Of <(T>)>)
System.ComponentModel..::.BindingList<(Of <(T>)>)
此类型的任何公共 static(在 Visual Basic 中为 Shared) 成员都是线程安全的。但不保证所有实例成员都是线程安全的。
Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360
.NET Framework 和 .NET Compact Framework 并不是对每个平台的所有版本都提供支持。有关支持的版本的列表,请参见.NET Framework 系统要求。
.NET Framework
受以下版本支持:3.5、3.0、2.0
.NET Compact Framework
受以下版本支持:3.5、2.0
XNA Framework
受以下版本支持:2.0、1.0
参考