例说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。

　　当绑定数据源的某属性值改变时,它可以通知客户端,并进行界面数据更新.而我们不用写很多复杂的代码来更新界面数据,这样可以做到方法简洁而清晰,INotifyPropertyChanged确实是一个强大的接口。

　　首先，我们需要了解如下有关Silverlight 2.0 数据绑定的术语:

　　Binding - 将绑定目标对象的属性与数据源联接起来

　　Source - 绑定的数据源

　　Mode - 绑定的数据流的方向 [System.Windows.Data.BindingMode枚举]

　　BindingMode.OneTime - 一次绑定。创建绑定时一次性地更新绑定目标对象的属性

　　BindingMode.OneWay - 单向绑定(默认值)。数据源的改变会自动通知到绑定目标对象的属性

　　BindingMode.TwoWay - 双向绑定。数据源或绑定目标对象的属性的值发生改变时会互相通知。显然，做数据验证的话一定要是双向绑定

　　INotifyPropertyChanged - 向客户端发出某一属性值已更改的通知

　　IValueConverter - 值转换接口，将一个类型的值转换为另一个类型的值。它提供了一种将自定义逻辑应用于绑定的方式

 

下面来实现INotifyPropertyChanged 接口的类

public  class User: INotifyPropertyChanged       // 类
    {
 
        private string _Name;
        public string Name
        {
            get { return this._Name; }
            set
            {
                this._Name = value;
                notifyPropertyChanged("Name");
            }
        }

        private bool sex;

        public bool Sex
        {
            get { return sex; }
            set
            {
                sex = value;
                notifyPropertyChanged("Sex");
            }
        }

        private int _Age;
        public int Age
        {
            get { return this._Age; }
            set
            {
                this._Age = value;
                notifyPropertyChanged("Age");
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;

         public void notifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

     }

 

MainWindow.XAML:

 

<Window xmlns:my="clr-namespace:WpfApplication1"  x:Class="WpfApplication1.MainWindow"
        xmlns=" http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x=" http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" >
   
<DockPanel  >
        <Grid  Height="300" Width="300" Background="#FFDE3030">
            <TextBlock Text="姓名：" Margin="42,38,130,237"  />
            <TextBox x:Name="tbName" Width="100" Height="30" Margin="107,35,93,235"  Text="{Binding Name, Mode=TwoWay}" />
            <TextBlock Text="年龄：" Margin="42,69,199,204" TextTrimming="None" />
            <TextBox x:Name="tbAge" Width="100" Height="30" Margin="107,66,93,204" Text="{Binding Age,Mode=TwoWay}"/>
            <CheckBox  x:Name="cbxSex" Content="性别" IsChecked="{Binding Sex,Mode=TwoWay}" Height="16" HorizontalAlignment="Left" Margin="224,35,0,0" VerticalAlignment="Top" Width="62" />
            
        </Grid>

    </DockPanel>
</Window>

     /// <summary>
    /// MainWindow.xaml 后台代码    /// </summary>
    public partial class MainWindow : Window
    {
        User Myuser = new User();

        public MainWindow()
        {
            InitializeComponent();
            Myuser = new User();
            Myuser.Name = "刘李杰";
            Myuser.Age = 23;

            tbName.DataContext = Myuser;
            tbAge.DataContext = Myuser;
            cbxSex.DataContext = Myuser;
            Myuser.PropertyChanged += new System.ComponentModel.PropertyChangedEventHandler(Myuser_PropertyChanged);

        }

        void Myuser_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            MessageBox.Show(e.PropertyName.ToString()+"改变");
        }