无法为填充的 TreeView 节点触发 SelectedNodeChanged 事件

Posted 2023-03-27

【中文标题】无法为填充的 TreeView 节点触发 SelectedNodeChanged 事件

【英文标题】：Not able to fire SelectedNodeChanged event for populated TreeView node

【发布时间】：2015-11-14 19:41:30

【问题描述】：

我需要在我的代码上动态生成几个树视图，并且我希望能够按需加载节点。我有以下代码结构。我的问题是填充的 TreeView 节点的 SelectedNodeChanged 事件不会触发。运行下面的代码示例后，如果将子节点展开到多个级别，然后单击子节点，则标签将不会显示文本并且填充的节点会折叠。任何想法表示赞赏！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class TreeViewTest : System.Web.UI.Page

    private const int Count = 2;
    private string[] codeList =  "th", "os" ;

    protected void Page_Load(object sender, EventArgs e)
    
        updateTree();
    


    protected void updateTree()
    

        treePanel.Controls.Clear();
        TreeView[] treeList = new TreeView[Count];

        for (int i = 0; i < Count; i++)
        
            var tree = new TreeView();
            tree.ID = "treelist" + i.ToString();

            tree.TreeNodePopulate += TreeBranch_SelectedNodePopulate;
            tree.SelectedNodeChanged += TreeBranch_SelectedNodeChanged;
            string codeName = codeList[i];
            TreeNode codeNode = new TreeNode(codeName, codeName);
            codeNode.SelectAction = TreeNodeSelectAction.Select;
            codeNode.PopulateOnDemand = true;
            tree.Nodes.Add(codeNode);
            tree.ExpandDepth = 2;
            treePanel.Controls.Add(tree);
            treeList[i] = tree;
        
    

    protected void TreeBranch_SelectedNodeChanged(object sender, EventArgs e)
    
        TreeView treeview = (TreeView)sender;
        string text = treeview.SelectedNode.Text;
        Label1.Text = text;
    


    protected void TreeBranch_SelectedNodePopulate(object sender, TreeNodeEventArgs e)
    
        LoadChildNode(e.Node);
    


    public void LoadChildNode(TreeNode parentNode)
    
        TreeNode childNode = new TreeNode("childNode","childNode");
        parentNode.ChildNodes.Add(childNode);
        childNode.PopulateOnDemand = true;
    

【问题讨论】：

您能否在声明树视图的位置显示代码，如UpdateFilterTreeView 中所示，显示其完整代码。

我添加了更多代码，看看是否有帮助。

只有SelectedNodeChanged 事件没有触发或者两者都没有触发？

使用treePanel.Controls.Clear(); 而不是treePanel.Dispose();

@X-TECH SelectNodeChanged 事件仅在节点被填充时才会触发

【参考方案1】：

试试下面的代码。

treePanel.Controls.Clear();
TreeView[] treeList = new TreeView[codebaseCount]; //But I recommend you use List<TreeView> instead of TreeView[];
for (int i = 0; i < codebaseCount; i++)

    var tree = new TreeView();
    tree.ID = "treelist" + i.ToString();
    tree.TreeNodePopulate += TreeBranch_SelectedNodePopulate;
    tree.SelectedNodeChanged += TreeBranch_SelectedNodeChanged;
    TreeNode newNode = new TreeNode(newName,newName);
    newNode.SelectAction = TreeNodeSelectAction.None;
    newNode.Expand();
    tree.Nodes.Add(newNode);
    tree.ExpandDepth = 2;
    treePanel.Controls.Add(tree);
    treeList[i] = tree;        
    // more code ...