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)。
代码语言：javascript复制 1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Drawing;
5 using System.Runtime.CompilerServices;
6 using System.Windows.Forms;
7
8 // Change the namespace to the project name.
9 namespace TestNotifyPropertyChangedCS
10 {
11 // This form demonstrates using a BindingSource to bind
12 // a list to a DataGridView control. The list does not
13 // raise change notifications. However the DemoCustomer type
14 // in the list does.
15 public partial class Form1 : Form
16 {
17 // This button causes the value of a list element to be changed.
18 private Button changeItemBtn = new Button();
19
20 // This DataGridView control displays the contents of the list.
21 private DataGridView customersDataGridView = new DataGridView();
22
23 // This BindingSource binds the list to the DataGridView control.
24 private BindingSource customersBindingSource = new BindingSource();
25
26 public Form1()
27 {
28 InitializeComponent();
29
30 // Set up the "Change Item" button.
31 this.changeItemBtn.Text = "Change Item";
32 this.changeItemBtn.Dock = DockStyle.Bottom;
33 this.changeItemBtn.Click =
34 new EventHandler(changeItemBtn_Click);
35 this.Controls.Add(this.changeItemBtn);
36
37 // Set up the DataGridView.
38 customersDataGridView.Dock = DockStyle.Top;
39 this.Controls.Add(customersDataGridView);
40
41 this.Size = new Size(400, 200);
42 }
43
44 private void Form1_Load(object sender, EventArgs e)
45 {
46 // Create and populate the list of DemoCustomer objects
47 // which will supply data to the DataGridView.
48 BindingList<DemoCustomer> customerList = new BindingList<DemoCustomer>();
49 customerList.Add(DemoCustomer.CreateNewCustomer());
50 customerList.Add(DemoCustomer.CreateNewCustomer());
51 customerList.Add(DemoCustomer.CreateNewCustomer());
52
53 // Bind the list to the BindingSource.
54 this.customersBindingSource.DataSource = customerList;
55
56 // Attach the BindingSource to the DataGridView.
57 this.customersDataGridView.DataSource =
58 this.customersBindingSource;
59
60 }
61
62 // Change the value of the CompanyName property for the first
63 // item in the list when the "Change Item" button is clicked.
64 void changeItemBtn_Click(object sender, EventArgs e)
65 {
66 // Get a reference to the list from the BindingSource.
67 BindingList<DemoCustomer> customerList =
68 this.customersBindingSource.DataSource as BindingList<DemoCustomer>;
69
70 // Change the value of the CompanyName property for the
71 // first item in the list.
72 customerList[0].CustomerName = "Tailspin Toys";
73 customerList[0].PhoneNumber = "(708)555-0150";
74 }
75
76 }
77
78 // This is a simple customer class that
79 // implements the IPropertyChange interface.
80 public class DemoCustomer : INotifyPropertyChanged
81 {
82 // These fields hold the values for the public properties.
83 private Guid idValue = Guid.NewGuid();
84 private string customerNameValue = String.Empty;
85 private string phoneNumberValue = String.Empty;
86
87 public event PropertyChangedEventHandler PropertyChanged;
88
89 // This method is called by the Set accessor of each property.
90 // The CallerMemberName attribute that is applied to the optional propertyName
91 // parameter causes the property name of the caller to be substituted as an argument.
92 private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
93 {
94 if (PropertyChanged != null)
95 {
96 PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
97 }
98 }
99
100 // The constructor is private to enforce the factory pattern.
101 private DemoCustomer()
102 {
103 customerNameValue = "Customer";
104 phoneNumberValue = "(312)555-0100";
105 }
106
107 // This is the public factory method.
108 public static DemoCustomer CreateNewCustomer()
109 {
110 return new DemoCustomer();
111 }
112
113 // This property represents an ID, suitable
114 // for use as a primary key in a database.
115 public Guid ID
116 {
117 get
118 {
119 return this.idValue;
120 }
121 }
122
123 public string CustomerName
124 {
125 get
126 {
127 return this.customerNameValue;
128 }
129
130 set
131 {
132 if (value != this.customerNameValue)
133 {
134 this.customerNameValue = value;
135 NotifyPropertyChanged();
136 }
137 }
138 }
139
140 public string PhoneNumber
141 {
142 get
143 {
144 return this.phoneNumberValue;
145 }
146
147 set
148 {
149 if (value != this.phoneNumberValue)
150 {
151 this.phoneNumberValue = value;
152 NotifyPropertyChanged();
153 }
154 }
155 }
156 }
157 }
