使用所有节点和子节点过滤 TreeView

Question

我有一个 parent 节点，它有一个 child，这个 child 有另一个 child 等等。它们都在 TreeView

所以我创建了一个全局变量来保存我所有的节点：

private TreeNodeCollection ProjectTreeView { get; set; }

然后我将树节点的数据设置到我的全局变量中：

ProjectTreeView = this.tvProjectList.Nodes[0].Nodes;

当我点击一个按钮时，我想过滤我的 TreeView，所以我首先清除 TreeView，然后我遍历集合并只显示满足我条件的节点：

private void rdoIssued_Click(object sender, EventArgs e)
{
    //blocks repainting tree till all objects loaded
    this.tvProjectList.BeginUpdate();
    this.tvProjectList.Nodes.Clear();

    foreach (TreeNode projectNode in ProjectTreeView)
    {
        if (bool.Parse(projectNode.Tag.ToString().Split('|')[8]) == true)
        {
            this.tvProjectList.Nodes.Add((TreeNode)projectNode.Clone());
        }

    }

    //enables redrawing tree after all objects have been added
    this.tvProjectList.EndUpdate();
}

问题是它只克隆第一个节点而不是 children。如何克隆具有所有 children 的节点？[=14=]

Answer 1

反其道而行之就容易多了。您可以遍历所有节点以保留过滤后的节点并删除其余节点。首先为0级节点创建备份

public partial class YourForm : Form
{
    public YourForm()
    {
        InitializeComponent();
        //...

        BackUpTree();
    }

    private List<TreeNode> ProjectTreeView = new List<TreeNode>();

    private void BackUpTree()
    {
        if (ProjectTreeView.Count == 0)
            foreach (TreeNode tn in tvProjectList.Nodes)
                ProjectTreeView.Add(tn.Clone() as TreeNode);
    }

创建一个方法来重置原始树：

    private void ResetTree(bool expandAll = false)
    {
        tvProjectList.BeginUpdate();
        tvProjectList.Nodes.Clear();

        foreach (var tn in ProjectTreeView)
            tvProjectList.Nodes.Add(tn.Clone() as TreeNode);

        if (expandAll) tvProjectList.ExpandAll();
        tvProjectList.EndUpdate();
    }

获取所有节点的迭代器函数：

    private IEnumerable<TreeNode> GetAllNodes(TreeNodeCollection Nodes)
    {
        foreach (TreeNode tn in Nodes)
        {
            yield return tn;

            foreach (TreeNode child in GetAllNodes(tn.Nodes))
                yield return child;
        }
    }

...以及执行过滤部分的方法：

    private void FilterTree(bool expandAll = false)
    {
        ResetTree(); // <- comment if you are doing multiple filters...
        tvProjectList.BeginUpdate();

        //.Reverse() is required here to iterate backward because the collections
        //are modified when removing nodes. You can call .ToList() instead to 
        //iterate forward.
        foreach (var node in GetAllNodes(tvProjectList.Nodes).Reverse())
        {
            if (bool.Parse(projectNode.Tag.ToString().Split('|')[8]) == false)
                if (node.Parent is null)
                    tvProjectList.Nodes.Remove(node);
                else
                    node.Parent.Nodes.Remove(node);
        }

        if (expandAll) tvProjectList.ExpandAll();
        tvProjectList.EndUpdate();
    }
}

使用所有节点和子节点过滤 TreeView

Filter TreeView with all nodes and childs

c#

treeview

winforms