在树中显示列表就像时尚

Question

我有一个以下的数据列表，我想在树中像时尚一样显示。 我能够显示两个级别的子文件夹（顺序）。但这个问题是 它可以有任意数量的子文件夹。看起来像递归是要走的路 但不知道如何继续。有什么帮助吗？

样本数据

ItemName ItemID NodeID ParentNodeID NodeName
            0   100   null         Node1
Item1       123 100   null         
Item2       124 100   null         
            0   101   null         Node2   
Item3       125 101   null         
Item4       126 101   null         
            0   103   101          Node3   
Item5       127 103   null         
            0   104   103          Node4
Item6       128 104   null         
            0   105   null          Node5   
Item5       127 105   null    

预期产出

Node1
     ------Item1
     ------Item2
Node2
     ------Item3
     ------Item4
     ------Node3
                --------Item5
                --------Node4
                            ------Item6
Node5
    -------Item5

我尝试了什么

Loop through my data
If parentnodeid is null
   find in the list object whether folder exists 
      if so append an item to it and add to the list
      else create folder and add to the list
else
   process sub folder
   if itemid = 0 
      find in the list whether the folder exist
          if so, append to the parent folder and add to the list
   else
      add the item to the list
end if

Answer 1

我有一些建议来实现你的目标：

- 递归是真正的方式

- 让您的数据更简单

- 以相同的方式处理项目和节点

示例数据

NodeName NodeID ParentNodeID 
Node1       1   0
Node2       2   0
Node3       3   2
Node4       4   3
Node5       5   0
Item1       6   1            
Item2       7   1   
Item3       8   2   
Item4       9   2    
Item5       10  3
Item6       11  4
Item5       12  5

下载代码将其转换为树视图

    SampleDataTable = new DataTable();
    SampleDataTable.Columns.Add("NodeName", typeof(string));
    SampleDataTable.Columns.Add("NodeID", typeof(int));
    SampleDataTable.Columns.Add("ParentNodeID", typeof(int));

    //Insert sample data to this table
    SampleDataTable.Rows.Add("Node1", 1, 0);
    SampleDataTable.Rows.Add("Node2", 2, 0);
    SampleDataTable.Rows.Add("Node3", 3, 2);
    SampleDataTable.Rows.Add("Node4", 4, 3);
    SampleDataTable.Rows.Add("Node5", 5, 0);
    SampleDataTable.Rows.Add("Item1", 6, 1);
    SampleDataTable.Rows.Add("Item2", 7, 1);
    SampleDataTable.Rows.Add("Item3", 8, 2);
    SampleDataTable.Rows.Add("Item4", 9, 2);
    SampleDataTable.Rows.Add("Item5", 10, 3);
    SampleDataTable.Rows.Add("Item6", 11, 4);
    SampleDataTable.Rows.Add("Item7", 12, 5);



   treeView1.Nodes.Clear();
    foreach (DataRow dr in SampleDataTable.Rows)
    {
        if ((int)dr["ParentNodeID"] == 0)
        {
            TreeNode parentNode = new TreeNode();
            parentNode .Text = dr["NodeName"].ToString();
            string value = dr["NodeID"].ToString();
            treeView1.Nodes.Add(parentNode);
            findNode(parentNode, value);
        }
    }

    public void findNode(TreeNode parent, string Id)
    {
        IEnumerable<DataRow> rows = SampleDataTable.Select("ParentNodeID=" + Id);

        foreach (DataRow dr in rows)
        {
            //Create child node
            TreeNode child = new TreeNode();
            child.Text = dr["NodeName"].ToString().Trim();

            parent.Nodes.Add(child);

            //Add more child nodes recursively
            findNode(child, dr["NodeID"].ToString());
        }

    }

Answer 2

如果您想将其打印为文本，我可以通过此帖https://stackoverflow.com/a/1649223/2966790

获取此方法

稍微调整一下

        SampleDataTable = new DataTable();
        SampleDataTable.Columns.Add("NodeName", typeof(string));
        SampleDataTable.Columns.Add("NodeID", typeof(int));
        SampleDataTable.Columns.Add("ParentNodeID", typeof(int));

        //Insert sample data to this table
        SampleDataTable.Rows.Add("Node1", 1, 0);
        SampleDataTable.Rows.Add("Node2", 2, 0);
        SampleDataTable.Rows.Add("Node3", 3, 2);
        SampleDataTable.Rows.Add("Node4", 4, 3);
        SampleDataTable.Rows.Add("Node5", 5, 0);
        SampleDataTable.Rows.Add("Item1", 6, 1);
        SampleDataTable.Rows.Add("Item2", 7, 1);
        SampleDataTable.Rows.Add("Item3", 8, 2);
        SampleDataTable.Rows.Add("Item4", 9, 2);
        SampleDataTable.Rows.Add("Item5", 10, 3);
        SampleDataTable.Rows.Add("Item6", 11, 4);
        SampleDataTable.Rows.Add("Item7", 12, 5);

        Node tree = new Node();

        foreach (DataRow dr in SampleDataTable.Rows)
        {
            if ((int)dr["ParentNodeID"] == 0)
            {
                Node parentNode = new Node();
                parentNode.Name = dr["NodeName"].ToString();
                string value = dr["NodeID"].ToString();
                tree.Children.Add(parentNode);
                findNode(parentNode, value);
            }
        }

        PrintPretty(tree, "   ", true);

用于填充树并打印它的函数：

    public void findNode(Node parent, string Id)
    {
        IEnumerable<DataRow> rows = SampleDataTable.Select("ParentNodeID=" + Id);

        foreach (DataRow dr in rows)
        {
            //Create child node
            Node child = new Node();
            child.Name = dr["NodeName"].ToString().Trim();

            parent.Children.Add(child);

            //Add more child nodes recursively
            findNode(child, dr["NodeID"].ToString());
        }

    }

    public void PrintPretty(Node node, string indent, bool last)
    {            
        textBox1.AppendText(indent);
        if (last)
        {
            textBox1.AppendText("\\-");
            indent += "  ";
        }
        else
        {
            textBox1.AppendText("|-");
            indent += "| ";
        }
        textBox1.AppendText(node.Name + Environment.NewLine);

        List<Node> Children = node.Children;

        for (int i = 0; i < Children.Count; i++)
            PrintPretty(Children[i], indent, i == Children.Count - 1);
    }

节点类：

public class Node
{
    public string Name; // method name
    public List<Node> Children;
}

结果：

Answer 3

伪请以此为指导：

// setup and call function:
string indent = "";
var toplevel = nodelist.Where(x => x.itemid == 0 && x.parentid == null).ToList();
displaytree(toplevel,indent);


// recursive function
displaytree(List<node> display,string indent)
{
   foreach(item in display)
   {
      Console.WriteLine(indent+item.NodeName);

      foreach(inneritem in nodelist.Where(x => item.nodeid == x.nodeid && x.itemid != null)
      {
          Console.WriteLine(indent+"------"+inneritem.NodeName);
      }
      displaytree(nodelist.Where(x => x.parentid == item.nodeid),indent+"    ");
   }
}