BindingList<T> 類別

定義

generic <typename T>
public ref class BindingList : System::Collections::ObjectModel::Collection<T>, System::ComponentModel::IBindingList, System::ComponentModel::ICancelAddNew, System::ComponentModel::IRaiseItemChangedEvents

[System.Serializable]
public class BindingList<T> : System.Collections.ObjectModel.Collection<T>, System.ComponentModel.IBindingList, System.ComponentModel.ICancelAddNew, System.ComponentModel.IRaiseItemChangedEvents

public class BindingList<T> : System.Collections.ObjectModel.Collection<T>, System.ComponentModel.IBindingList, System.ComponentModel.ICancelAddNew, System.ComponentModel.IRaiseItemChangedEvents

[<System.Serializable>]
type BindingList<'T> = class
    inherit Collection<'T>
    interface IBindingList
    interface IList
    interface ICollection
    interface IEnumerable
    interface ICancelAddNew
    interface IRaiseItemChangedEvents

type BindingList<'T> = class
    inherit Collection<'T>
    interface ICollection
    interface IEnumerable
    interface IList
    interface IBindingList
    interface ICancelAddNew
    interface IRaiseItemChangedEvents

Public Class BindingList(Of T)
Inherits Collection(Of T)
Implements IBindingList, ICancelAddNew, IRaiseItemChangedEvents

類型參數

繼承

Object

Collection<T>

BindingList<T>

屬性

SerializableAttribute

實作

ICollection IEnumerable IList IBindingList ICancelAddNew IRaiseItemChangedEvents

範例

以下範例示範綁定到 BindingList<T> 包含業務物件的元件。 這是一個包含方法 Main 的完整範例。

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;

namespace BindingListOfTExamples;

public partial class Form1 : Form
{
    readonly TextBox textBox2;
    readonly ListBox listBox1;
    readonly Button button1;
    readonly TextBox textBox1;
    readonly Random randomNumber = new();

    public Form1()
    {
        AutoScaleMode = AutoScaleMode.Font;
        textBox1 = new TextBox();
        textBox2 = new TextBox();
        listBox1 = new ListBox();
        button1 = new Button();
        textBox1.Location = new Point(169, 26);
        textBox1.Size = new Size(100, 20);
        textBox1.Text = "Bracket";
        textBox2.Location = new Point(169, 57);
        textBox2.ReadOnly = true;
        textBox2.Size = new Size(100, 20);
        textBox2.Text = "4343";
        listBox1.FormattingEnabled = true;
        listBox1.Location = new Point(12, 12);
        listBox1.Size = new Size(120, 95);
        button1.Location = new Point(180, 83);
        button1.Size = new Size(75, 23);
        button1.Text = "Add New Item";
        button1.Click += button1_Click;
        ClientSize = new Size(292, 266);
        Controls.Add(button1);
        Controls.Add(listBox1);
        Controls.Add(textBox2);
        Controls.Add(textBox1);
        Text = "Parts Form";
        Load += Form1_Load;
    }

    void Form1_Load(object sender, EventArgs e)
    {
        InitializeListOfParts();
        listBox1.DataSource = listOfParts;
        listBox1.DisplayMember = "PartName";
        listOfParts.AddingNew += listOfParts_AddingNew;
        listOfParts.ListChanged += listOfParts_ListChanged;
    }

    // Declare a new BindingListOfT with the Part business object.
    BindingList<Part> listOfParts;
    void InitializeListOfParts()
    {
        // Create the new BindingList of Part type.
        listOfParts = new BindingList<Part>
        {
            // Allow new parts to be added, but not removed once committed.        
            AllowNew = true,
            AllowRemove = false,

            // Raise ListChanged events when new parts are added.
            RaiseListChangedEvents = true,

            // Do not allow parts to be edited.
            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.
    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
{
    public Part() { }
    public Part(string nameForPart, int numberForPart)
    {
        PartName = nameForPart;
        PartNumber = numberForPart;
    }

    public string PartName { get; set; }

    public int PartNumber { get; set; }
}

Option Explicit On
Option Strict On
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

    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

備註

此 BindingList<T> 類別可作為基底類別，建立雙向資料綁定機制。 BindingList<T> 提供一個具體且通用的 IBindingList 介面實作。 這是實現完整IBindingList介面的替代方案，因為完整介面因 、 IEditableObject與 CurrencyManager之間的微妙互動IBindingList而較為困難。 然而，典型的解決方案程式設計師會使用提供資料綁定功能的類別，例如 BindingSource，而非直接使用 BindingList<T>。

BindingList<T> 透過可 AddNew 擴充方法支援工廠建立的實例。 （類似的可擴展性也存在於其他類別中，例如 BindingSource）此外，由於此類別實作了介面，ICancelAddNew它能透過 and CancelNew 方法對新項目EndNew進行交易提交或回滾。

另請參閱

• IBindingList
• ICancelAddNew
• IEditableObject
• IRaiseItemChangedEvents
• CurrencyManager
• BindingSource