检查父节点时自动检查子节点

Question

我在 VS 2012 中使用 .net c# 并尝试编写一个函数来自动检查已检查父树视图节点的所有子节点。我是 c# 编程新手，所以我发现了以下代码，但它有两个问题：

1. if (HasChildNodes(node)) Visual Studio 报告 HasChildNodes 行未知。
2. 我想从单击检查的选定节点开始，并且我认为代码会遍历整个树？

谢谢你的帮助。

        treeView.BeginUpdate();
        //Loop through all the nodes of tree
        foreach (TreeNode node in treeView.Nodes)
        {
            //If node has child nodes
            if (HasChildNodes(node))
            {
                if (node.Checked == true)
                {
                    //Check all the child nodes.
                    foreach (TreeNode childNode in node.Nodes)
                    {
                        childNode.Checked = true;
                    }
                }
            }
        }
        treeView.EndUpdate();

Answer 1

以下是树视图示例的工作代码，其中检查和取消检查子节点和父节点（添加树视图并将名称指定为 tvwDynamic）

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

命名空间 Treeview { 公共部分类 Form1 : Form { 公共 Form1() { InitializeComponent(); } }

    private void Form1_Load(object sender, EventArgs e)
    {
        TreeNode MainNode = new TreeNode("Java");
        tvwDynamic.Nodes.Add(MainNode);
        MainNode = new TreeNode("PHP");
        tvwDynamic.Nodes.Add(MainNode);           
        TreeNode node2 = new TreeNode("C#");
        TreeNode node3 = new TreeNode("VB.NET");
        TreeNode[] childNodes = new TreeNode[] {node2,node3};
        MainNode = new TreeNode("ASP.NET", childNodes);
        tvwDynamic.Nodes.Add(MainNode);
         TreeNode node4 = new TreeNode("Winforms");
        TreeNode node5 = new TreeNode("Webforms");
          TreeNode[] SubchildNodes = new TreeNode[] {node4,node5};
        MainNode =  new TreeNode("Test",SubchildNodes);
        tvwDynamic.Nodes[2].Nodes[1].Nodes.Add(MainNode);
        tvwDynamic.CheckBoxes = true;

    }

    private void tvwDynamic_AfterCheck(object sender, TreeViewEventArgs e)
    {
        if (e.Action != TreeViewAction.Unknown)
        {

            if (e.Node.Nodes.Count > 0)
            {

                /* Calls the CheckAllChildNodes method, passing in the current 

                Checked value of the TreeNode whose checked state changed. */

                this.CheckAllChildNodes(e.Node, e.Node.Checked);

            }

        }

        SelectParents(e.Node, e.Node.Checked);

    }
    private void CheckAllChildNodes(TreeNode treeNode, bool nodeChecked)
    {

        foreach (TreeNode node in treeNode.Nodes)
        {

            node.Checked = nodeChecked;

            if (node.Nodes.Count > 0)
            {

                // If the current node has child nodes, call the CheckAllChildsNodes method recursively.

                this.CheckAllChildNodes(node, nodeChecked);

            }

        }

    }


    private void SelectParents(TreeNode node, Boolean isChecked)
    {
        var parent = node.Parent;

        if (parent == null)
            return;

        if (!isChecked && HasCheckedNode(parent))
            return;

        parent.Checked = isChecked;
        SelectParents(parent, isChecked);
    }

    private bool HasCheckedNode(TreeNode node)
    {
        return node.Nodes.Cast<TreeNode>().Any(n => n.Checked);
    }
} }