WPF数据绑定的树形视图展开/折叠

Question

我想找到一种方法，通过绑定对象来控制TreeView节点的展开/折叠。对象具有IsExpanded属性，我希望根据该属性显示TreeView节点本身展开或折叠。

这是我的代码：

C#:

public partial class Window2 : Window
{
    public Window2()
    {
        InitializeComponent();

        this.DataContext = new List<Parent>() { Base.GetParent("Parent 1"), Base.GetParent("Parent 2") };
    }
}

public class Base
{
    public string Name { get; set; }
    public bool IsExpanded { get; set; }

    public static Parent GetParent(string name)
    {
        Parent p = new Parent() { Name = name };

        p.Children.Add(new Child() { Name = "Child 1", GrandChildren = new ObservableCollection<GrandChild>() { new GrandChild() { Name = "Grandchild 1" } } });
        p.Children.Add(new Child() { Name = "Child 2", GrandChildren = new ObservableCollection<GrandChild>() { new GrandChild() { Name = "Grandchild 1" } } });
        p.Children.Add(new Child() { Name = "Child 3", GrandChildren = new ObservableCollection<GrandChild>() { new GrandChild() { Name = "Grandchild 1" } } });

        return p;
    }
}

public class Parent : Base
{
    public ObservableCollection<Child> Children { get; set; }

    public Parent()
    {
        this.Children = new ObservableCollection<Child>();
    }
}

public class Child : Base
{
    public ObservableCollection<GrandChild> GrandChildren { get; set; }

    public Child()
    {
        this.GrandChildren = new ObservableCollection<GrandChild>();
    }
}

public class GrandChild : Base
{
}

XAML：

<Window x:Class="HeterogeneousExperimentExplorer.Window2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:HeterogeneousTree"
    Title="Window2" Height="300" Width="300">
    <Window.Resources>
        <HierarchicalDataTemplate DataType="{x:Type local:Parent}" ItemsSource="{Binding Children}">
            <TextBlock Text="{Binding Name}" />
            <HierarchicalDataTemplate.ItemTemplate>
                <HierarchicalDataTemplate DataType="{x:Type local:Parent}" ItemsSource="{Binding GrandChildren}">
                    <TextBlock Text="{Binding Name}" />
                    <HierarchicalDataTemplate.ItemTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Name}" />
                        </DataTemplate>
                    </HierarchicalDataTemplate.ItemTemplate>
                </HierarchicalDataTemplate>
            </HierarchicalDataTemplate.ItemTemplate>
        </HierarchicalDataTemplate>
    </Window.Resources>
    <Grid>
        <TreeView ItemsSource="{Binding}" />
    </Grid>
</Window>

- Carlo

Answer 1

提出了解决方案：

<Style TargetType="{x:Type TreeViewItem}">
    <Setter Property="IsExpanded" Value="{Binding IsNodeExpanded}"/>
</Style>

因此，该样式获取绑定到TreeViewItem的对象并查看其IsNodeExpanded属性，并将该值分配给TreeViewItem.IsExpanded属性。如果添加Mode = TwoWay，则它们将彼此通知（TreeViewItem将在展开时告诉对象）。

- Carlo

---

现在已经晚了（晚了9年），但是你把Style元素放在XML的哪个位置了？ - NirMH

@NirMH 应该放在 TreeView.Resources 中。 - Krzysztof Skowronek

请记得在代码中加入 Mode=TwoWays 以实现完整功能。 - Krzysztof Skowronek

还有一个有用的链接 https://dev59.com/w3I_5IYBdhLWcg3wMf9_ - Sergey Orlov