WPF TreeView数据绑定详解

发布时间:2023-05-22

一、绑定方式

在使用WPF TreeView进行数据绑定的时候,常见的几种方式有以下几种。

  1. 使用静态数据源
<TreeView>
    <TreeViewItem Header="节点1">
        <TreeViewItem Header="节点1子节点1" />
        <TreeViewItem Header="节点1子节点2" />
    </TreeViewItem>
    <TreeViewItem Header="节点2">
        <TreeViewItem Header="节点2子节点1" />
        <TreeViewItem Header="节点2子节点2" />
    </TreeViewItem>
</TreeView>
  1. 使用Binding绑定动态数据源
public class TreeNode
{
    public string Header { get; set; }
    public ObservableCollection<TreeNode> Children { get; set; }
}
public class TreeViewModel
{
    public ObservableCollection<TreeNode> RootNodes { get; set; }
}
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new TreeViewModel() { RootNodes = /*your observable collection here*/ };
    }
}
<Window>
    <TreeView ItemsSource="{Binding RootNodes}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                <TextBlock Text="{Binding Header}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>
</Window>

二、绑定到TreeViewItem

有时候,需要将数据绑定到TreeViewItem本身,并使用该数据去匹配TreeViewItem的模板。可以使用 DataTemplate

<Window.Resources>
    <DataTemplate DataType="{x:Type local:TreeNode}">
        <TextBlock Text="{Binding Header}" />
    </DataTemplate>
</Window.Resources>
<Window>
    <TreeView ItemsSource="{Binding RootNodes}">
        <TreeView.ItemContainerStyle>
            <Style TargetType="{x:Type TreeViewItem}">
                <Setter Property="IsExpanded" Value="True" />
                <Setter Property="Header" Value="{Binding}" />
            </Style>
        </TreeView.ItemContainerStyle>
    </TreeView>
</Window>

三、绑定到TreeViewItem的Header

另外一种常见的 TreeView 数据绑定方式,是将数据绑定到 TreeViewItem 的 Header 属性,方法同样是使用 DataTemplate。这种方式可以在 TreeView 显示多种风格和数据类型的节点。

<Window>
    <Window.Resources>
        <DataTemplate DataType="{x:Type local:TreeNode}">
            <StackPanel Orientation="Horizontal">
                <Image Source="{Binding ImageUri}" Width="16" Height="16" />
                <TextBlock Margin="5,0,0,0" Text="{Binding Header}" />
            </StackPanel>
        </DataTemplate>
    </Window.Resources>
    <TreeView ItemsSource="{Binding RootNodes}">
        <TreeView.ItemContainerStyle>
            <Style TargetType="{x:Type TreeViewItem}">
                <Setter Property="IsExpanded" Value="True" />
            </Style>
        </TreeView.ItemContainerStyle>
    </TreeView>
</Window>

四、MVVM绑定

在 MVVM 模式中,ViewModel 是数据的源头,View 则是呈现数据的界面,二者通过数据绑定实现解耦。使用 MVVM 模式实现 WPF TreeView 数据绑定是非常常见的,以下是一个简单的示例。

public class TreeNodeViewModel
{
    public string Header { get; set; }
    public ObservableCollection<TreeNodeViewModel> Children { get; set; }
}
public class TreeViewViewModel : INotifyPropertyChanged
{
    public ObservableCollection<TreeNodeViewModel> RootNodes { get; set; }
    private TreeNodeViewModel _selectedNode;
    public TreeNodeViewModel SelectedNode
    {
        get { return _selectedNode; }
        set
        {
            _selectedNode = value;
            OnPropertyChanged("SelectedNode");
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;
    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new TreeViewViewModel() { RootNodes = /*your observable collection here*/ };
    }
}
<Window>
    <TreeView ItemsSource="{Binding RootNodes}" SelectedItem="{Binding SelectedNode}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                <TextBlock Text="{Binding Header}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>
</Window>

五、数据排序

WPF TreeView 提供了对节点的默认排序,可以按字母顺序排序、降序排序等。此外,也可以实现自定义排序。

public class TreeNode : IComparable
{
    public string Header { get; set; }
    public ObservableCollection<TreeNode> Children { get; set; }
    public int CompareTo(object obj)
    {
        TreeNode other = obj as TreeNode;
        if (other == null) return 0;
        return Header.CompareTo(other.Header);
    }
}
<Window>
    <TreeView ItemsSource="{Binding RootNodes}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                <TextBlock Text="{Binding Header}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
        <TreeView.ItemContainerStyle>
            <Style TargetType="{x:Type TreeViewItem}">
                <Setter Property="IsExpanded" Value="True" />
            </Style>
        </TreeView.ItemContainerStyle>
        <TreeView.Items.SortDescriptions>
            <scm:SortDescription PropertyName="Header" Direction="Ascending" />
        </TreeView.Items.SortDescriptions>
    </TreeView>
</Window>