尽管在Silverlight Toolkit中有相关的DEMO来演示如何使用TreeView控件，但其还是有一些功能没被演示出来。因为在我们平时开发过程中，数据是被动态查询获取的(不是DEMO中的静态文件方式)。因此今天就演示一下如何使用WCF来获取相应数据并使用TreeView来动态加载相应结点信息。
首先，我们要创建一个WCF服务来获取相应的树形节点数据信息，如下：
public class ForumInfo
{
public int ForumID { get; set; }
public int ParendID { get; set; }
public string ForumName { get; set; }
}
[ServiceContract(Namespace = "")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class DateService
{
[OperationContract]
public List GetForumData()
{
List forumList = new List();
forumList.Add(new ForumInfo() { ForumID = 1, ParendID = 0, ForumName = "笔记本版块"});
forumList.Add(new ForumInfo() { ForumID = 2, ParendID = 0, ForumName = "台式机版块" });
forumList.Add(new ForumInfo() { ForumID = 3, ParendID = 1, ForumName = "Dell笔记本" });
forumList.Add(new ForumInfo() { ForumID = 4, ParendID = 1, ForumName = "IBM笔记本" });
forumList.Add(new ForumInfo() { ForumID = 5, ParendID = 4, ForumName = "IBM-T系列" });
forumList.Add(new ForumInfo() { ForumID = 6, ParendID = 4, ForumName = "IBM-R系列" });
forumList.Add(new ForumInfo() { ForumID = 7, ParendID = 2, ForumName = "联想台式机" });
forumList.Add(new ForumInfo() { ForumID = 8, ParendID = 2, ForumName = "方正台式机" });
forumList.Add(new ForumInfo() { ForumID = 9, ParendID = 2, ForumName = "HP台式机" });
forumList.Add(new ForumInfo() { ForumID = 10, ParendID = 7, ForumName = "联想家悦H系列" });
forumList.Add(new ForumInfo() { ForumID = 11, ParendID = 7, ForumName = "联想IdeaCentre系列" });
return forumList;
}
}
从代码中可看出，ForumInfo是使用ParendID来记录父结点信息并以此来创建一个树形结构的，而方法：
GetForumData()即是演示了我们平时查询数据的过程。我们在Silverlight中添加对该服务的引用即可。
我们在Silverlight中添加对Silverlight Toolkit相关DLL引用，然后向XAML文件上拖入一个TREEVIEW 控件。并将其命名为“TreeOfLife”，最后我们再放几个TextBlock来显示树形结点被点击后显示的相应的 ForumInfo信息。最后XAML中的内容如下所示：
<controls:TreeView x:Name="TreeOfLife" Margin="5" Grid.Column="0" Grid.Row="1"
SelectedItemChanged="TreeOfLife_SelectedItemChanged" />
<Border BorderBrush="Gray" BorderThickness="1" Padding="8" Margin="8,0,0,0" Grid.Row="1" Grid.Column="1">
<StackPanel x:Name="DetailsPanel" Margin="4">
<StackPanel Orientation="Horizontal">
<TextBlock Text="版块ID: " FontWeight="Bold" />
<TextBlock Text="{Binding ForumID}" />
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock Text="版块名称: " FontWeight="Bold" />
<TextBlock Text="{Binding ForumName}" />
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock Text="版块信息: " FontWeight="Bold" />
<TextBlock x:Name="DetailText" TextWrapping="Wrap" Text="{Binding ForumName}"/>
</StackPanel>
</StackPanel>
</Border>
下面是相应的XAML.CS文件中的内容，主要是使用递归方式遍历数据列表并创建相关的结点信息：
public partial class Page : UserControl
{
DateServiceClient dataServiceClient = new DateServiceClient();
ObservableCollection forumList = new ObservableCollection();
public Page()
{
InitializeComponent();
//此样式只添加在根结点上
//TreeOfLife.ItemContainerStyle = this.Resources["RedItemStyle"] as Style;
dataServiceClient.GetForumDataCompleted+=new EventHandler(dataServiceClient_GetForumDataCompleted);
dataServiceClient.GetForumDataAsync();
}
void dataServiceClient_GetForumDataCompleted(object sender, GetForumDataCompletedEventArgs e)
{
try
{
forumList = e.Result;
AddTreeNode(0, null);
}
catch
{
throw new NotImplementedException();
}
}
private void AddTreeNode(int parentID, TreeViewItem treeViewItem)
{
List result = (from forumInfo in forumList
where forumInfo.ParendID == parentID
select forumInfo).ToList();
if (result.Count > 0)
{
foreach (ForumInfo foruminfo in result)
{
TreeViewItem objTreeNode = new TreeViewItem();
objTreeNode.Header = foruminfo.ForumName;
objTreeNode.DataContext = foruminfo;
//此样式将会添加的所有叶子结点上
//objTreeNode.ItemContainerStyle = this.Resources["RedItemStyle"] as Style;
//添加根节点
if (treeViewItem == null)
{
TreeOfLife.Items.Add(objTreeNode);
}
else
{
treeViewItem.Items.Add(objTreeNode);
}
AddTreeNode(foruminfo.ForumID, objTreeNode);
}
}
}
private void TreeOfLife_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs
private void TreeOfLife_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
TreeViewItem item = e.NewValue as TreeViewItem;
ForumInfo fi = item.DataContext as ForumInfo;
DetailsPanel.DataContext = fi;
}
}
下面演示一下效果，如下图所示：
当前TreeView控件还支持样式定义，比如可以给每个树形结点前添加CheckBox和一个小图标，这里我们使用下面样式：
<UserControl.Resources>
<Style x:Key="RedItemStyle" TargetType="controls:TreeViewItem">
<Setter Property="HeaderTemplate">
<Setter.Value>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox />
<Image Source="image/default.png"/>
<TextBlock Text="{Binding}" Foreground="Red" FontStyle="Italic" />
</StackPanel>
</DataTemplate>
</Setter.Value>
</Setter>
<Setter Property="IsExpanded" Value="True" />
</Style>
</UserControl.Resources>
然后在cs文件中使用下面语句将该样式绑定到TreeView上：
TreeOfLife.ItemContainerStyle = this.Resources["RedItemStyle"] as Style;
下面就是应用了该样式的运行效果：
当前TreeView中定义样式模版还可以使用ItemTemplate，下面是一段样式代码:
<controls:TreeView.ItemTemplate>
<controls:HierarchicalDataTemplate ItemsSource="{Binding Subclasses}"
ItemContainerStyle="{StaticResource ExpandedItemStyle}">
<StackPanel>
<TextBlock Text="{Binding Rank}" FontSize="8" FontStyle="Italic" Foreground="Gray" Margin="0 0 0 -5" />
<TextBlock Text="{Binding Classification}" />
</StackPanel>
</controls:HierarchicalDataTemplate>
</controls:TreeView.ItemTemplate>
