多重HierarchicalDataTemplate

Question

我在WPF中的TreeView有一些问题。我有三个互相包含的藏品。所以，我有一个组类型，其中有一个MasterActions ObservableCollection。在MasterAction中有一个SlaveActions ObservableCollection。组、MasterAction和SlaveAction类具有描述属性。我想将它们绑定到TreeView。我尝试过HierarchicalDataTemplate结构，但它不起作用。

有Xaml代码：

<TreeView x:Name="TreeViewResult" HorizontalAlignment="Stretch" ItemsSource="{Binding}" VerticalAlignment="Stretch"  Margin="10,10,10,10" >
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate ItemsSource="{Binding Groups}">
            <StackPanel Orientation="Horizontal">
                <TextBlock Margin="3" Text="{Binding Description}"/>
            </StackPanel>
            <HierarchicalDataTemplate.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding MasterActions}">
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding Description}"/>
                    </StackPanel>
                    <HierarchicalDataTemplate.ItemTemplate>
                        <HierarchicalDataTemplate ItemsSource="{Binding SlaveActions}">
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="{Binding Description}"/>
                            </StackPanel>
                        </HierarchicalDataTemplate>
                    </HierarchicalDataTemplate.ItemTemplate>
                </HierarchicalDataTemplate>
            </HierarchicalDataTemplate.ItemTemplate>
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

代码背后：

Handler handler = new Handler();
Group group1 = new Group("group1_description");
MasterAction masterAction11 = new MasterAction("masterAction11");
SlaveAction slaveAction111 = new SlaveAction("slaveAction111");
SlaveAction slaveAction112 = new SlaveAction("slaveAction112");
MasterAction masterAction12 = new MasterAction("masterAction12");
MasterAction masterAction13 = new MasterAction("masterAction13");
SlaveAction slaveAction131 = new SlaveAction("slaveAction131");
handler.Add(group1);
handler.Add(masterAction11);
handler.Add(slaveAction111);
handler.Add(slaveAction112);
handler.Add(masterAction12);
handler.Add(masterAction13);
handler.Add(slaveAction131);
Group group2 = new Group("group2_description");
MasterAction masterAction21 = new MasterAction("masterAction21");
MasterAction masterAction22 = new MasterAction("masterAction22");
SlaveAction slaveAction221 = new SlaveAction("slaveAction221");
SlaveAction slaveAction222 = new SlaveAction("slaveAction222");
SlaveAction slaveAction223 = new SlaveAction("slaveAction223");
SlaveAction slaveAction224 = new SlaveAction("slaveAction224");
handler.Add(group2);
handler.Add(masterAction21);
handler.Add(masterAction22);
handler.Add(slaveAction221);
handler.Add(slaveAction222);
handler.Add(slaveAction224);
TreeViewResult.ItemsSource = handler.Groups;

Handler.Add()是一个重载的方法。它管理所有的三个参数来构造树。

group1_description
    masterAction11
        slaveAction111
        slaveAction112
    masterAction12
    masterAction13
        slaveAction131
group2_description
    masterAction21
    masterAction22
        slaveAction221
        slaveAction222
        slaveAction223
        slaveAction224

当我运行代码时，它会生成下一个：

​

​

如何在正确的节点下显示所有MasterActions和SlaveActions描述？

提前谢谢。

Answer 1

看起来，如果您试图在HierarchicalDataTemplate中达到一个层次太深的程度。在代码中将ItemsSource设置为Groups

TreeViewResult.ItemsSource = handler.Groups;

实际上，您如何设置它(在代码中或通过绑定)并不重要，更重要的是顶级项是Group，并且将顶级HierarchicalDataTemplate.ItemsSource绑定到Groups。而不是将所有东西向上移动一个级别，并将顶级ItemsSource绑定到MasterActions，然后将下一个级别绑定到SlaveActions和最低层，这样就可以使用简单的DataTemplate来显示没有子节点的Description。

<TreeView 
    x:Name="TreeViewResult" 
    HorizontalAlignment="Stretch" 
    VerticalAlignment="Stretch"
    Margin="10,10,10,10" >
    <!-- top node will be a Group -->
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate ItemsSource="{Binding MasterActions}">
            <TextBlock Margin="3" Text="{Binding Description}"/>
            <!-- child node will be a MasterAction -->
            <HierarchicalDataTemplate.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding SlaveActions}">
                    <TextBlock Text="{Binding Description}"/>
                    <!-- leaf will be a SlaveAction -->
                    <HierarchicalDataTemplate.ItemTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Description}"/>
                        </DataTemplate>
                    </HierarchicalDataTemplate.ItemTemplate>
                </HierarchicalDataTemplate>
            </HierarchicalDataTemplate.ItemTemplate>
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

而且，与您的问题无关，但是由于您显示单个TextBlock，所以不需要StackPanel