深入浅出WPF之Binding--笔记(2015.03.03)

将上篇的this.listBoxStudents.DisplayMemberPath = "Name";注释。然后XAML代码改为：

        <StackPanel x:Name="stackPanel" Background="LightBlue">
        <TextBlock Text="Student ID:" FontWeight="Bold" Margin="5"/>
        <TextBox x:Name="textBoxId" Margin="5"/>
        <TextBlock Text="Student List:" FontWeight="Bold" Margin="5"/>
        <ListBox x:Name="listBoxStudents" Height="110" Margin="5">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding Id}" Width="30"/>
                        <TextBlock Text="{Binding Name}" Width="60"/>
                        <TextBlock Text="{Binding Age}" Width="30"/>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </StackPanel>

    在集合类型作为列表控件的ItemSource时，一般会考虑使用ObservableCollection<T>代替List<T>,因为ObservableCollection<T>类实现了INotifyCollectionChanged和INotifyPropertyChanged接口，能把集合的变化立刻通知显示它的列表控件，改变会立即显现出来。

    当使用XML数据作为Binding的Source时，使用XPath而不是Path属性来指定数据的来源。

XML:

    <?xml version="1.0" encoding="utf-8"?>
<StudentList>
     <Student Id = "1">
          <Name>Tim</Name>
     </Student>
     <Student Id = "2">
          <Name>Tom</Name>
     </Student>
     <Student Id = "3">
          <Name>Vena</Name>
     </Student>
     <Student Id = "4">
          <Name>Emily</Name>
     </Student>
</StudentList>

XAML:

        <StackPanel Background="LightBlue">
        <ListView x:Name="listViewStudent" Height="130" Margin="5">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Id" Width="80" DisplayMemberBinding="{Binding XPath=@Id}"/>
                    <GridViewColumn Header="Name" Width="120" DisplayMemberBinding="{Binding XPath=Name}"/>
                </GridView>
            </ListView.View>
        </ListView>
        <Button Content="Load" Click="Button_Click" Height="25" Margin="5"/>
    </StackPanel>

C#代码：

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            XmlDocument doc = new XmlDocument();
            doc.Load("RawData.xml");

            XmlDataProvider xdp = new XmlDataProvider();
            xdp.Document = doc;
            xdp.XPath = @"/StudentList/Student";
            this.listViewStudent.DataContext = xdp;
            this.listViewStudent.SetBinding(ListView.ItemsSourceProperty, new Binding());
        }
    }

XmlDataProvider还有一个名为Source的属性，可以用它直接指定XML文档所在的位置。上面代码的C#部分可改为：

        private void Button_Click(object sender, RoutedEventArgs e)
        {

            XmlDataProvider xdp = new XmlDataProvider();
            xdp.Source = new Uri(@"E:\RawData.xml"); //这里是绝对Uri
            xdp.XPath = @"/StudentList/Student";
            this.listViewStudent.DataContext = xdp;
            this.listViewStudent.SetBinding(ListView.ItemsSourceProperty, new Binding());
        }