深入浅出WPF 第二部分(26)

XML最大的优势是可以方便地表示带有层级的数据，同时WPF准备了TreeView和MenuView控件用来显示层级数据。能够帮助层级控件显示层级数据的模板是HierarchicalDataTemplate。

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <!--数据源-->
        <XmlDataProvider x:Key="ds" Source="Data.xml" XPath="Data/Grade"/>
        <!--年级模板-->
        <HierarchicalDataTemplate DataType="Grade" ItemsSource="{Binding XPath=Class}">
            <TextBlock Text="{Binding XPath=@Name}"/>
        </HierarchicalDataTemplate>
        <!--班级模板-->
        <HierarchicalDataTemplate DataType="Class" ItemsSource="{Binding XPath=Group}">
            <RadioButton Content="{Binding XPath=@Name}"/>
        </HierarchicalDataTemplate>
        <!--小组模板-->
        <HierarchicalDataTemplate DataType="Group" ItemsSource="{Binding XPath=Student}">
            <CheckBox Content="{Binding XPath=@Name}"/>
        </HierarchicalDataTemplate>
    </Window.Resources>
    <Grid>
        <TreeView Margin="5" ItemsSource="{Binding Source={StaticResource ResourceKey=ds}}"/>
    </Grid>
</Window>

<?xml version="1.0" encoding="utf-8" ?>
<Data xmlns="">
  <Grade Name="一年级">
    <Class Name="一班">
      <Group Name="A组"/>
      <Group Name="B组"/>
      <Group Name="C组"/>
    </Class>
    <Class Name="二班">
      <Group Name="A组"/>
    </Class>
    <Class Name="三班">
      <Group Name="A组"/>
      <Group Name="B组"/>
      <Group Name="C组"/>
    </Class>
  </Grade>
  <Grade Name="二年级">
    <Class Name="一班">
      <Group Name="A组"/>
      <Group Name="B组"/>
    </Class>
    <Class Name="二班">
      <Group Name="A组"/>
      <Group Name="B组"/>
      <Group Name="C组"/>
      <Group Name="D组"/>
    </Class>
  </Grade>
</Data>

同一种数据类型的嵌套结构只设计一个HierchicalDataTemplate就可以了，它会自动产生迭代应用的效果。

<?xml version="1.0" encoding="utf-8" ?>
<Data xmlns="">
  <Operation Name="文件" Gesture="F">
    <Operation Name="新建" Gesture="N">
      <Operation Name="项目" Gesture="Control + P" />
      <Operation Name="网站" Gesture="Control + W" />
      <Operation Name="文档" Gesture="Control + D" />
    </Operation>
    <Operation Name="保存" Gesture="S" />
    <Operation Name="打印" Gesture="P" />
    <Operation Name="退出" Gesture="X" />
  </Operation>
  <Operation Name="编辑" Gesture="E">
    <Operation Name="拷贝" Gesture="Control + C" />
    <Operation Name="剪切" Gesture="Control + F" />
    <Operation Name="粘帖" Gesture="Control + V" />
  </Operation>
</Data>

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <!--数据源-->
        <XmlDataProvider x:Key="ds" Source="Data_2.xml" XPath="Data/Operation"/>

        <HierarchicalDataTemplate DataType="Operation" ItemsSource="{Binding XPath=Operation}">
            <StackPanel Orientation="Vertical">
                <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
                    <TextBlock Text="{Binding XPath=@Name}"/>
                    <TextBlock Text="("/>
                    <TextBlock Text="{Binding XPath=@Gesture}"/>
                    <TextBlock Text=")"/>
                </StackPanel>
            </StackPanel>
        </HierarchicalDataTemplate>
    </Window.Resources>
    <Grid MenuItem.Click="MenuItem_Click">
        <Menu Margin="5" ItemsSource="{Binding Source={StaticResource ResourceKey=ds}}"/>
    </Grid>
</Window>

        private void MenuItem_Click(object sender, RoutedEventArgs e)
        {
            MenuItem mi = e.OriginalSource as MenuItem;
            //HierarchicalDataTemplate的作用目标不是MenuItem的内容，而是它的Header。如果针对MenuItem的单击事件进行侦听处理，
            //我们就可以从被单击的Menultem的Header中取出XML数据。
            XmlElement ele = mi.Header as XmlElement;
            MessageBox.Show(string.Format("Operation Name: {0}", ele.Attributes["Name"].Value));
        }