WPF TreeView HierarchicalDataTemplate - 绑定到具有多个子集合的对象 [英] WPF TreeView HierarchicalDataTemplate - binding to object with multiple child collections

问题描述

我正在尝试使用 TreeView 来绑定我的集合，以便所有组都显示嵌套组，并且每个组都将显示条目.

I am trying to get a TreeView to bind my collection so that all groups show nested groups and each group will show entry.

如何使用 HierarchicalDataTemplate 以便 TreeView 处理子组和条目集合?

How can I use the HierarchicalDataTemplate so that the TreeView will process both SubGroups and Entries collection?

组显示子组和条目:

Example:
Group1
--Entry
--Entry
Group2
--Group4
----Group1
------Entry
------Entry
----Entry
----Entry
--Entry
--Entry
Group3
--Entry
--Entry

namespace TaskManager.Domain
{
    public class Entry
    {
        public int Key { get; set; }
        public string Name { get; set; }
    }
}

namespace TaskManager.Domain
{
    public class Group
    {
        public int Key { get; set; }
        public string Name { get; set; }

        public IList<Group> SubGroups { get; set; }
        public IList<Entry> Entries { get; set; }
    }
}

测试数据:

---

namespace DrillDownView
{
    public class TestData
    {

        public IList<Group> Groups = new List<Group>();

        public void Load()
        {
            Group grp1 = new Group() { Key = 1, Name = "Group 1", SubGroups = new List<Group>(), Entries = new List<Entry>() };
            Group grp2 = new Group() { Key = 2, Name = "Group 2", SubGroups = new List<Group>(), Entries = new List<Entry>() };
            Group grp3 = new Group() { Key = 3, Name = "Group 3", SubGroups = new List<Group>(), Entries = new List<Entry>() };
            Group grp4 = new Group() { Key = 4, Name = "Group 4", SubGroups = new List<Group>(), Entries = new List<Entry>() };

            //grp1
            grp1.Entries.Add(new Entry() { Key=1, Name="Entry number 1" });
            grp1.Entries.Add(new Entry() { Key=2, Name="Entry number 2" });
            grp1.Entries.Add(new Entry() { Key=3,Name="Entry number 3" });

            //grp2
            grp2.Entries.Add(new Entry(){ Key=4, Name = "Entry number 4"});
            grp2.Entries.Add(new Entry(){ Key=5, Name = "Entry number 5"});
            grp2.Entries.Add(new Entry(){ Key=6, Name = "Entry number 6"});

            //grp3
            grp3.Entries.Add(new Entry(){ Key=7, Name = "Entry number 7"});
            grp3.Entries.Add(new Entry(){ Key=8, Name = "Entry number 8"});
            grp3.Entries.Add(new Entry(){ Key=9, Name = "Entry number 9"});

            //grp4
            grp4.Entries.Add(new Entry(){ Key=10, Name = "Entry number 10"});
            grp4.Entries.Add(new Entry(){ Key=11, Name = "Entry number 11"});
            grp4.Entries.Add(new Entry(){ Key=12, Name = "Entry number 12"});

            grp4.SubGroups.Add(grp1);
            grp2.SubGroups.Add(grp4);

            Groups.Add(grp1);
            Groups.Add(grp2);
            Groups.Add(grp3);
        }
    }
}

XAML:

---

<Window x:Class="DrillDownView.Window2"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:TaskManager.Domain;assembly=TaskManager.Domain"
        Title="Window2" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>

        <TreeView Name="GroupView" Grid.Row="0" Grid.Column="0" ItemsSource="{Binding}">
            <TreeView.Resources>
                <HierarchicalDataTemplate DataType="{x:Type local:Group}" ItemsSource="{Binding SubGroups}">
                    <TextBlock Text="{Binding Path=Name}" />
                </HierarchicalDataTemplate>
                <HierarchicalDataTemplate DataType="{x:Type local:Entry}" ItemsSource="{Binding Entries}">
                    <TextBlock Text="{Binding Path=Name}" />
                </HierarchicalDataTemplate>
            </TreeView.Resources>
        </TreeView>
    </Grid>
</Window>

XAML.CS:

---

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

    private void LoadView()
    {
        TestData data = new TestData();
        data.Load();
        GroupView.ItemsSource = data.Groups;
    }
}

推荐答案

HierarchicalDataTemplate 是一种表达这就是渲染此类对象的方式，这里有一个可以被探测的属性"的方式找到这个对象下的子节点'

A HierarchicalDataTemplate is a way of saying 'this is how you render this type of object and here is a property that can be probed to find the child nodes under this object'

因此，您需要一个返回此节点的子节点"的属性.例如(如果你不能让 Group 和 Entry 都派生自一个共同的 Node 类型)

Therefore you need a single property that returns the 'children' of this node. e.g. (If you can't make both Group and Entry derive from a common Node type)

public class Group{ ....
        public IList<object> Items
        {
            get
            {
                IList<object> childNodes = new List<object>();
                foreach (var group in this.SubGroups)
                    childNodes.Add(group);
                foreach (var entry in this.Entries)
                    childNodes.Add(entry);

                return childNodes;
            }
        }

接下来您不需要 HierarchicalDataTemplate 条目，因为条目没有子项.因此需要更改 XAML 以使用新的 Items 属性和 DataTemplate 用于条目:

Next you don't need a HierarchicalDataTemplate for entry since an entry doesn't have children. So the XAML needs to be changed to use the new Items property and a DataTemplate for Entry:

<TreeView Name="GroupView" Grid.Row="0" Grid.Column="0" ItemsSource="{Binding}">
    <TreeView.Resources>
        <HierarchicalDataTemplate DataType="{x:Type local:Group}" ItemsSource="{Binding Items}">
            <TextBlock Text="{Binding Path=Name}" />
        </HierarchicalDataTemplate>
        <DataTemplate DataType="{x:Type local:Entry}" >
            <TextBlock Text="{Binding Path=Name}" />
        </DataTemplate>
    </TreeView.Resources>
</TreeView>

这就是它的样子.

这篇关于WPF TreeView HierarchicalDataTemplate - 绑定到具有多个子集合的对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！