WPF 数据绑定树视图展开/折叠 [英] WPF DataBound treeview expand / collapse

问题描述

我只是想找到一种方法来通过它们绑定到的对象来控制 TreeView 节点的展开/折叠.该对象有一个 IsExpanded 属性，我想用它来显示基于该属性展开或折叠的 TreeView 节点本身.

I'm just trying to find a way to control the expand / collapse of the TreeView nodes through the object they're bound to. The object has an IsExpanded property, and I want to use that to show the TreeView node itself expanded or collapsed based on that property.

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>

推荐答案

想出了解决方案:

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

因此样式获取绑定到 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，它们会相互通知(TreeViewItem 会在对象展开时通知对象).

So the style gets the object bound to the TreeViewItem and looks at its IsNodeExpanded attribute and it assigns that value to the TreeViewItem.IsExpanded property. If you add Mode=TwoWay, they'll notify each other (TreeViewItem will tell the object when it has been expanded).

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