INotifyPropertyChanged 接口

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。

上述这两个功能不要同时实现。

示例

下面的代码示例演示如何实现 INotifyPropertyChanged 接口。在运行此示例时，您将注意到绑定的 DataGridView 控件无需重置绑定即能反映数据源中的更改。如果使用 CallerMemberName 属性，对 NotifyPropertyChanged 方法不必指定属性名称作为字符串参数。有关详细信息，请参阅Caller Information (C# and Visual Basic)。

 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(, );
         }

         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[].CustomerName = "Tailspin Toys";
             customerList[].PhoneNumber = "[phone]";
         }

     }

     // 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 = "[phone]";
         }

         // 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();
                 }
             }
         }
     }
 }

转自微软官网技术文章：

https://msdn.microsoft.com/zh-cn/library/system.componentmodel.inotifypropertychanged(v=vs.110).aspx?cs-save-lang=1&cs-lang=csharp#code-snippet-2