在Silverlight中使用HierarchicalDataTemplate为TreeView实现递归树状结构

这是项目中一个页面上的一个功能。我们需要在界面上通过一个TreeView控件显示一个递归的树状结构，也就是说会很多层嵌套的节点，而且层数是不确定的。

这个功能，可以通过HierarchicalDataTemplate来很方便地实现

1. 业务实体

作为举例，我定义了一个大家都很熟悉的Folder类型，即文件夹。我们都知道，文件夹又可以包含子文件夹，而且可以多层嵌套。所以，这是一个递归的结构体。

    public class Folder    {        public string Name { get; set; }        public ObservableCollection Folders { get; set; }    }

.csharpcode, .csharpcode pre{font-size: small;color: black;font-family: consolas, "Courier New", courier, monospace;background-color: #ffffff;/*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt {background-color: #f4f4f4;width: 100%;margin: 0em;}.csharpcode .lnum { color: #606060; }

2. 准备数据

我用下面的代码，模拟一个数据读取操作。下面是硬编码出来的数据。实际情况下，可以读取数据库。

        void MainPage_Loaded(object sender, RoutedEventArgs e)        {            var result = new[]{                new Folder(){Name="Test",Folders =new ObservableCollection(                    new[]{                        new Folder(){Name="Test4"},                        new Folder(){Name="Test3"},                        new Folder(){Name="Test4",Folders=new ObservableCollection(                            new []{new Folder(){Name ="Test5"}})                        }                    })}};            tvFolders.ItemsSource = result;        }

.csharpcode, .csharpcode pre{font-size: small;color: black;font-family: consolas, "Courier New", courier, monospace;background-color: #ffffff;/*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt {background-color: #f4f4f4;width: 100%;margin: 0em;}.csharpcode .lnum { color: #606060; }

3. 绑定控件

<UserControl x:Class="SilverlightTreeviewSample.MainPage"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    mc:Ignorable="d"    d:DesignHeight="300" d:DesignWidth="400" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk">        <UserControl.Resources>        <sdk:HierarchicalDataTemplate x:Key="FolderItemTemplate" ItemsSource="{Binding Folders}">            <TextBlock Text="{Binding Name}">TextBlock>        sdk:HierarchicalDataTemplate>        <Style TargetType="sdk:TreeViewItem">            <Setter Property="IsExpanded" Value="True">Setter>        Style>           UserControl.Resources>    <Grid x:Name="LayoutRoot" Background="White">        <sdk:TreeView  Name="tvFolders" ItemTemplate="{StaticResource FolderItemTemplate}">          sdk:TreeView>    Grid>UserControl>

请注意，我们这里用到一个特殊的DataTemplate：HierarchicalDataTemplate，并且将其设置为Treeview的ItemTemplate。.csharpcode, .csharpcode pre{font-size: small;color: black;font-family: consolas, "Courier New", courier, monospace;background-color: #ffffff;/*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt {background-color: #f4f4f4;width: 100%;margin: 0em;}.csharpcode .lnum { color: #606060; }

 

4. 查看效果