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一步一步学Silverlight :数据绑定

作者: TerryLee  来源: 博客园  发布时间: 2008-10-08 18:14  阅读: 36679 次  推荐: 1   原文链接   [收藏]  
[1] 一步一步学Silverlight :数据绑定
[2] 一步一步学Silverlight :数据绑定
[3] 一步一步学Silverlight :数据绑定

单向绑定示例

如果需要在数据源发生变化时能够通知UI进行相应的更新,即使用单向绑定OneWay或者双向绑定TwoWay,则业务实体需要实现接口INotifyPropertyChanged。在本示例中,我们加上一个更新按钮,当单击按钮时更新user实例的属性值,会看到界面上的数据也会发生变化。

修改一下User类,使其实现INotifyPropertyChanged接口。

public class User : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private string _name;
    public string Name
    {
        get { return _name; }
        set 
        {
            _name = value;
            if(PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs("Name"));
            }
        }
    }

    private string _address;
    public string Address
    {
        get { return _address; }
        set 
        {
            _address = value;
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs("Address"));
            }
        }
    }
}

修改数据绑定模式,使用单向绑定OneWay模式,如{Binding Address, Mode=OneWay}

<Grid x:Name="LayoutRoot" Background="#46461F">
    <Grid.RowDefinitions>
        <RowDefinition Height="160"></RowDefinition>
        <RowDefinition Height="40"></RowDefinition>
        <RowDefinition Height="40"></RowDefinition>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="150"></ColumnDefinition>
        <ColumnDefinition Width="*"></ColumnDefinition>
    </Grid.ColumnDefinitions>
    <Image Source="terrylee.jpg" Width="78" Height="100"
       HorizontalAlignment="Left" Grid.Row="0" Grid.Column="1"/>
    <Button x:Name="btnUpdate" Width="100" Height="40"
            Content="Update" Click="btnUpdate_Click"/>
    <TextBlock Foreground="White" FontSize="18" Text="姓名:"
           Grid.Row="1" Grid.Column="0" HorizontalAlignment="Right"/>
    <TextBlock x:Name="lblName" Foreground="White" FontSize="18"
               Grid.Row="1" Grid.Column="1" HorizontalAlignment="Left"
               Text="{Binding Name, Mode=OneWay}"/>
    <TextBlock Foreground="White" FontSize="18" Text="位置:"
               Grid.Row="2" Grid.Column="0" HorizontalAlignment="Right"/>
    <TextBlock x:Name="lblAddress" Foreground="White" FontSize="18"
               Grid.Row="2" Grid.Column="1" HorizontalAlignment="Left"
               Text="{Binding Address, Mode=OneWay}"/>
</Grid>

编写事件处理程序,为了演示把user声明为一个全局的,并在按钮的单击事件中修改其属性值:

public partial class Page : UserControl
{
    public Page()
    {
        InitializeComponent();
    }
    User user;
    private void UserControl_Loaded(object sender, RoutedEventArgs e)
    {
        user = new User();
        user.Name = "TerryLee";
        user.Address = "中国 天津";

        lblName.DataContext = user;
        lblAddress.DataContext = user;
    }

    private void btnUpdate_Click(object sender, RoutedEventArgs e)
    {
        user.Name = "李会军";
        user.Address = "China Tianjin";
    }
}

运行后如下所示:

TerryLee_Silverlight2_0056

单击Update按钮后:

TerryLee_Silverlight2_0057

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