asp.net treeview 仅展开选定的父级

Question

我在 asp.net 中使用 Treeview
如果我选择任何父节点，那么它应该展开，其他父节点应该在页面回发(导航)之后折叠......我使用下面的代码。

 protected void Page_Load(object sender, EventArgs e)
{
 if (!IsPostBack)
        {
            if (Session["TreeViewState"] != null)
            {
                List<string> list = (List<string>)Session["TreeViewState"];
                RestoreTreeViewState(TreeViewApplicationSetup.Nodes, list);
            }
        }
        else
        {
            List<string> list = new List<string>(100);
            SaveTreeViewState(TreeViewApplicationSetup.Nodes, list);
            Session["TreeViewState"] = list;
        }
}



 private void SaveTreeViewState(TreeNodeCollection nodes, List<string> list)
    {
        Session["TreeViewState"] = null;
        foreach (TreeNode node in nodes)
        {
            if (node.ChildNodes != null)
            {
                if (node.Expanded.HasValue && node.Expanded == true && !String.IsNullOrEmpty(node.Text))
                {
                    list.Add(node.Text);
                }
                if (node.ShowCheckBox == true && node.ChildNodes.Count == 0 && node.Parent.Expanded == true)
                {
                    if (node.Checked == true)
                    {
                        list.Add(node.ValuePath + "-T");
                    }
                    else
                    {
                        list.Add(node.ValuePath + "-F");
                    }
                }
                SaveTreeViewState(node.ChildNodes, list);
            }
        }
    }
    private void RestoreTreeViewState(TreeNodeCollection nodes, List<string> list)
    {
        foreach (TreeNode node in nodes)
        {

            if (list.Contains(node.Text) || list.Contains(node.ValuePath + "-T") || list.Contains(node.ValuePath + "-F"))
            {
                if (node.ChildNodes != null && node.ChildNodes.Count != 0 && node.Expanded.HasValue && node.Expanded == false)
                {
                    if (node.Parent != null)
                    {
                        if (list.Contains(node.ChildNodes[0].ValuePath + "T") || list.Contains(node.ChildNodes[0].ValuePath + "-F"))
                        {
                            node.Expand();
                        }
                    }
                    else
                    {
                        node.Expand();
                    }
                }
                else if (node.ChildNodes != null && node.Expanded.HasValue && node.Expanded == false)
                {
                    if (node.ShowCheckBox == true && list.Contains(node.Parent.Text) && list.Contains(node.Parent.Parent.Text))
                    {
                        if (list.IndexOf(node.ValuePath + "-T") != -1)
                        {
                            node.Checked = true;

                        }
                        else if (list.IndexOf(node.ValuePath + "-F") != -1)
                        {
                            node.Checked = false;

                        }
                    }
                }
            }
            else
            {
                if (node.ChildNodes != null && node.ChildNodes.Count != 0 && node.Expanded.HasValue && node.Expanded == true)
                {
                    node.Collapse();
                }
            }
            if (node.ChildNodes != null && node.ChildNodes.Count != 0)
            {
                RestoreTreeViewState(node.ChildNodes, list);
            }
        }
    }

它的 jsut 帮助我在每个回发中扩展父节点，但其他父节点没有崩溃....

Answer 1

在您的 .aspx 文件中:

...
<asp:TreeView ID="Tree" runat="server" OnSelectedNodeChanged="Tree_SelectNodeChange">
...

然后在代码隐藏 Page_Load 中，您只需将数据绑定(bind)到 TreeView 并在 OnSelectedNodeChanged 处理程序中，您需要折叠所有节点，然后展开选定节点及其所有父节点:

protected void Tree_SelectNodeChange(object sender, EventArgs e)
{
    var tree = (TreeView)sender;
    foreach (TreeNode node in tree.Nodes)
    {
        node.CollapseAll();
    }
    ExpandToRoot(tree.SelectedNode);
}

private void ExpandToRoot(TreeNode node)
{
    node.Expand();
    if (node.Parent != null)
    {
        ExpandToRoot(node.Parent);
    }
}