INotifyPropertyChanged
它的作用:向客戶端發出某一屬性值已更改的通知。
當屬性改變時,它可以通知客戶端,並進行界面數據更新.而我們不用寫很多複雜的代碼來更新界面數據,這樣可以做到方法簡潔而清晰,鬆耦合和讓方法變得更通用.可用的地方太多了:例如上傳進度,實時後臺數據變更等地方。
它的作用:向客戶端發出某一屬性值已更改的通知。
當屬性改變時,它可以通知客戶端,並進行界面數據更新.而我們不用寫很多複雜的代碼來更新界面數據,這樣可以做到方法簡潔而清晰,鬆耦合和讓方法變得更通用.可用的地方太多了:例如上傳進度,實時後臺數據變更等地方.目前我發現winform和silverlight都支持,確實是一個強大的接口.
在構造函數中先綁定
public Class_Name()
{
User user = new User();
user.Name = "your name";
user.Address = "your address";
textBox1.Text = user.Name;
textBox2.Text = user.Address;
}
編寫一個簡單的業務類
按 Ctrl+C 複製代碼
publicclass User : INotifyPropertyChanged
{
publicevent PropertyChangedEventHandler PropertyChanged;
privatestring _name;
publicstring Name
{
get { return _name; }
set
{
_name = value;
if(PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs("Name"));
}
}
}
privatestring _address;
publicstring Address
{
get { return _address; }
set
{
_address = value;
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs("Address"));
}
}
}
}
按 Ctrl+C 複製代碼
ObservableCollection
綁定到集合
數據綁定的數據源對象可以是一個含有數據的單一對象，也可以是一個對象的集合。之前，一直在討論如何將目標對象與一個單一對象綁定。Silverlight中的數據綁定還能將目標對象與集合對象相綁定，這也是很常用的。比如顯示文章的題目列表、顯示一系列圖片等。
如果要綁定到一個集合類型的數據源對象，綁定目標可以使用ItemsControl，如ListBox或DataGrid等。另外，通過定製ItemsControl的數據模板（DataTemplate），還可以控制集合對象中每一項的顯示。
使用ObservableCollection
數據源集合對象必須繼承IEnumerable接口，爲了讓目標屬性與數據源集合的更新（不但包括元素的修改，還包括元素的增加和刪除）保持同步，數據源集合還必須實現INotifyPropertyChanged接口和INotifyCollectionChanged接口。
在Silverlight中創建數據源集合可以使用內建的ObservableCollection類，因爲ObservableCollection類既實現了INotifyPropertyChanged接口，又實現了INotifyCollectionChanged接口。使用ObservableCollection類不但可以實現Add、Remove、Clear和Insert操作，還可以觸發PropertyChanged事件。View Code本文轉載http://www.cnblogs.com/ynbt/archive/2013/01/02/2842385.html
// 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");
}
}
}
}View Code（2）、msdn經典例；當數據發生變化時候，DataGridView自動變化。繼承INotifyPropertyChanged接http://msdn.microsoft.com/zh-cn/library/system.componentmodel.inotifypropertychanged.aspx
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();
}
}
}
}
}View CodeBindingList<DemoCustomer> 如果換成List<DemoCustomer>，DataGridView必需調用DataGridView.Refresh();界面數據纔會即使更新。
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>();
List<DemoCustomer> customerList = new List<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.DataSource;
}
// 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>;
List<DemoCustomer> customerList =
this.customersBindingSource.DataSource as List<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";
//如果數據源是換成List<T>只有刷新以後才能即使更新。
this.customersDataGridView.Refresh();
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}
}
// 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");
}
}
}
}View Code（3）、讓INotifyPropertyChanged的實現更優雅一些http://tech.ddvip.com/2009-05/1242645380119734_2.html
很好，很強大，高端大氣上檔次
public class DemoCustomer1 : PropertyChangedBase
{
// These fields hold the values for the public properties.
private Guid idValue = Guid.NewGuid();
private string customerNameValue = String.Empty;
private string phoneNumberValue = String.Empty;
// The constructor is private to enforce the factory pattern.
private DemoCustomer1()
{
customerNameValue = "Customer";
phoneNumberValue = "(555)555-5555";
}
// This is the public factory method.
public static DemoCustomer1 CreateNewCustomer()
{
return new DemoCustomer1();
}
// 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;
this.NotifyPropertyChanged(p => p.CustomerName);
//NotifyPropertyChanged("CustomerName");
}
}
}
public string PhoneNumber
{
get
{
return this.phoneNumberValue;
}
set
{
if (value != this.phoneNumberValue)
{
this.phoneNumberValue = value;
this.NotifyPropertyChanged(p => p.PhoneNumber);
//NotifyPropertyChanged("PhoneNumber");
}
}
}
}
/// <summary>
/// 基類
/// </summary>
public class PropertyChangedBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
/// <summary>
/// 擴展方法
/// </summary>
public static class PropertyChangedBaseEx
{
public static void NotifyPropertyChanged<T, TProperty>(this T propertyChangedBase, Expression<Func<T, TProperty>> expression) where T : PropertyChangedBase
{
var memberExpression = expression.Body as MemberExpression;
if (memberExpression != null)
{
string propertyName = memberExpression.Member.Name;
propertyChangedBase.NotifyPropertyChanged(propertyName);
}
else
throw new NotImplementedException();
}
}View CodeView Code