如何：使用 BindingSource 和 INotifyPropertyChanged 接口引发更改通知

当数据源中包含的类型实现 INotifyPropertyChanged 并在属性值发生更改时引发 PropertyChanged 事件时，BindingSource 组件会自动检测数据源中的更改。 此更改检测非常有用，因为绑定到 BindingSource 的控件会在数据源值更改时自动更新。

备注

如果数据源实现 INotifyPropertyChanged 并且要执行异步操作，则不应对后台线程上的数据源进行更改。 相反，应读取后台线程上的数据，并将数据合并到 UI 线程上的列表中。

例

下面的代码示例演示 INotifyPropertyChanged 接口的简单实现。 它还显示了当 BindingSource 绑定到 INotifyPropertyChanged 类型的列表时，BindingSource 如何自动将数据源更改传递给绑定控件。

如果使用 CallerMemberName 属性，则对 NotifyPropertyChanged 方法的调用不必将属性名称指定为字符串参数。 有关详细信息，请参阅 来电者信息（C#） 或 调用方信息（Visual Basic）。

C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Runtime.CompilerServices;
using System.Windows.Forms;

// Change the namespace to the project name.
namespace TestNotifyPropertyChangedCS
{
    // This form demonstrates using a BindingSource to bind
    // a list to a DataGridView control. The list does not
    // raise change notifications. However the DemoCustomer type
    // in the list does.
    public partial class Form1 : Form
    {
        // This button causes the value of a list element to be changed.
        private Button changeItemBtn = new Button();

        // This DataGridView control displays the contents of the list.
        private DataGridView customersDataGridView = new DataGridView();

        // This BindingSource binds the list to the DataGridView control.
        private BindingSource customersBindingSource = new BindingSource();

        public Form1()
        {
            InitializeComponent();

            // Set up the "Change Item" button.
            this.changeItemBtn.Text = "Change Item";
            this.changeItemBtn.Dock = DockStyle.Bottom;
            this.changeItemBtn.Click +=
                new EventHandler(changeItemBtn_Click);
            this.Controls.Add(this.changeItemBtn);

            // Set up the DataGridView.
            customersDataGridView.Dock = DockStyle.Top;
            this.Controls.Add(customersDataGridView);

            this.Size = new Size(400, 200);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // Create and populate the list of DemoCustomer objects
            // which will supply data to the DataGridView.
            BindingList<DemoCustomer> customerList = new BindingList<DemoCustomer>();
            customerList.Add(DemoCustomer.CreateNewCustomer());
            customerList.Add(DemoCustomer.CreateNewCustomer());
            customerList.Add(DemoCustomer.CreateNewCustomer());

            // Bind the list to the BindingSource.
            this.customersBindingSource.DataSource = customerList;

            // Attach the BindingSource to the DataGridView.
            this.customersDataGridView.DataSource =
                this.customersBindingSource;
        }

        // Change the value of the CompanyName property for the first
        // item in the list when the "Change Item" button is clicked.
        void changeItemBtn_Click(object sender, EventArgs e)
        {
            // Get a reference to the list from the BindingSource.
            BindingList<DemoCustomer> customerList =
                this.customersBindingSource.DataSource as BindingList<DemoCustomer>;

            // Change the value of the CompanyName property for the
            // first item in the list.
            customerList[0].CustomerName = "Tailspin Toys";
            customerList[0].PhoneNumber = "(708)555-0150";
        }
    }

    // This is a simple customer class that
    // implements the IPropertyChange interface.
    public class DemoCustomer : INotifyPropertyChanged
    {
        // These fields hold the values for the public properties.
        private Guid idValue = Guid.NewGuid();
        private string customerNameValue = String.Empty;
        private string phoneNumberValue = String.Empty;

        public event PropertyChangedEventHandler PropertyChanged;

        // This method is called by the Set accessor of each property.
        // The CallerMemberName attribute that is applied to the optional propertyName
        // parameter causes the property name of the caller to be substituted as an argument.
        private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        // The constructor is private to enforce the factory pattern.
        private DemoCustomer()
        {
            customerNameValue = "Customer";
            phoneNumberValue = "(312)555-0100";
        }

        // This is the public factory method.
        public static DemoCustomer CreateNewCustomer()
        {
            return new DemoCustomer();
        }

        // This property represents an ID, suitable
        // for use as a primary key in a database.
        public Guid ID
        {
            get
            {
                return this.idValue;
            }
        }

        public string CustomerName
        {
            get
            {
                return this.customerNameValue;
            }

            set
            {
                if (value != this.customerNameValue)
                {
                    this.customerNameValue = value;
                    NotifyPropertyChanged();
                }
            }
        }

        public string PhoneNumber
        {
            get
            {
                return this.phoneNumberValue;
            }

            set
            {
                if (value != this.phoneNumberValue)
                {
                    this.phoneNumberValue = value;
                    NotifyPropertyChanged();
                }
            }
        }
    }
}

编译代码

此示例需要：

• 对 System、System.Data、System.Drawing 和 System.Windows.Forms 程序集的引用。

另请参阅

• INotifyPropertyChanged
• BindingSource 组件
• 如何：使用 BindingSource ResetItem 方法引发更改通知