INotifyPropertyChanged 接口

向客户端发出某一属性值已更改的通知。

命名空间：   System.ComponentModel
程序集：   System（在 System.dll 中）

语法 ：
public interface INotifyPropertyChanged

public interface class INotifyPropertyChanged

  

备注：

INotifyPropertyChanged 接口用于向客户端（通常是执行绑定的客户端）发出某一属性值已更改的通知。

例如，考虑一个带有名为 FirstName 属性的 Person 对象。
若要提供一般性属性更改通知，则 Person 类型实现 INotifyPropertyChanged 接口并在 FirstName 更改时引发 PropertyChanged 事件。

若要在将客户端与数据源进行绑定时发出更改通知，则绑定类型应具有下列任一功能：

• 实现 INotifyPropertyChanged 接口（首选）。

• 为绑定类型的每个属性提供更改事件。

不执行上述这两个功能。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Diagnostics;
using System.Drawing;
using System.Data.SqlClient;
using System.Windows.Forms;

// 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 class Form1 : System.Windows.Forms.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()
    {
        // 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( 800 , 200 );
        this .Load += new EventHandler(Form1_Load);
    }

    private void Form1_Load(System.Object sender, System.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 " ;
        customersBindingSource.ResetItem( 0 );
    }

    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run( new Form1());
    }
}

// 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;

    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null )
        {
            PropertyChanged( this , new PropertyChangedEventArgs(info));
        }
    }

    // The constructor is private to enforce the factory pattern.
    private DemoCustomer()
    {
        customerNameValue = " Customer " ;
        phoneNumberValue = " (555)555-5555 " ;
    }

    // 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( " CustomerName " );
            }
        }
    }

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

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