代码之家 › 专栏 › 技术社区 › viky

Wpf:我怎么知道TreeView是否更新了?

treeview events wpf c#

viky · 技术社区 · 15 年前

有没有办法知道树什么时候更新?我尝试了与TreeView绑定的ObservableCollection的CollectionChanged事件,但没有成功。

编辑:

我的代码如下:

class Temp
{
    public void Load()
    {
        DeriveA d1 = new DeriveA();
        DeriveB d2 = new DeriveB();
        DeriveB d3 = new DeriveB();
        DeriveC d4 = new DeriveC();
        DeriveC d5 = new DeriveC();
        d1.Items.Add(d2);
        d1.Items.Add(d3);
        d2.Items.Add(d4);
        d2.Items.Add(d5);
        
        List = new ObservableCollection<object>();
        List.Add(d1);
        tree.ItemsSource = List;

        DeriveC d6 = new DeriveC();
        d3.Items.Add(d6);        //At this point, I want to know that List got updated
    }
    
    public ObservableCollection<object> List
    {
        get;
        set;
    }
}

class Base
{
    ObservableCollection<Base> Items = new ObservableCollection<Base>();
}

class DeriveA : Base
{
}

class DeriveB : Base
{
}

class DeriveC : Base
{
}

如何查找列表属性何时在任何级别更新?

2 回复 | 直到 4 年前

Svetlozar Angelov 15 年前

那怎么办 SourceUpdated 事件?

SourceUpdated事件没有启动,但我尝试了ObservableCollection.CollectionChanged 它是好的,所以我想请你给一个小代码,这是我测试过的,希望它有帮助:

public partial class Window1 : Window
{
    ObservableCollection<string> items = new ObservableCollection<string>()
    {
        "string1","string2","string3","string4","string5"
    };
    public Window1()
    {
        InitializeComponent();
        DataContext = this;
        tree.ItemsSource = items;
        items.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(items_CollectionChanged);
    }

    void items_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        MessageBox.Show("Event raised");
    }


    private void btnAddItem_Click(object sender, RoutedEventArgs e)
    {
        items.Add("string6");
    }
}

还有xaml

<StackPanel Orientation="Vertical">
            <TreeView x:Name="tree" />
            <Button x:Name="btnAddItem" Click="btnAddItem_Click" Content="AddItem" />
</StackPanel>

Markus Hütter 15 年前

你可以这样做:

private void Loaded()
{
    MyTreeNode d1 = new MyTreeNode();
    MyTreeNode d2 = new MyTreeNode();
    MyTreeNode d3 = new MyTreeNode();
    MyTreeNode d4 = new MyTreeNode();
    MyTreeNode d5 = new MyTreeNode();
    d1.AddNode(d2);
    d1.AddNode(d3);
    d2.AddNode(d4);
    d2.AddNode(d5);

    d1.CollectionChanged += (s, e) =>
    {
        MessageBox.Show("Tree Changed");
    };

    MyTreeNode d6 = new MyTreeNode();
    d3.AddNode(d6);
}  

public class MyTreeNode : ObservableCollection<MyTreeNode>
{
    public void AddNode(MyTreeNode node)
    {
        this.Add(node);
        node.CollectionChanged += (s, e) => this.OnCollectionChanged(e);
    }
}