读取 csv 文件和 return 缩进菜单 c#

Question

我必须使用 .csv 文件中的以下数据创建缩进式导航菜单：

ID；MenuName；ParentID；isHidden；LinkURL
1；公司；NULL；False；/company
2；关于我们；1；False；/company/aboutus
3;任务;1;错误;/company/mission
4;团队;2;错误;/company/aboutus/团队
5;客户 2;10;错误; /references/client2
6；客户端 1；10；假；/references/client1
7；客户端 4；10；真；/references/client4
8；客户端 5;10;True;/references/client5
10;References;NULL;False;/references

我必须使用这些数据开发一个应用程序来解析文件并在控制台中显示内容，如下例所示：

。公司
.....关于我们
.......团队
.....使命
。参考文献
.....客户1
..客户2

菜单项应缩进（取决于父项），隐藏项 (isHidden==true) 不应显示，项应按字母顺序排列。到目前为止我试过：

using (StreamReader sr = new StreamReader(@"file.csv"))
        {
            // Read the stream to a string, and write the string to the console.
            string [] lines = sr.ReadToEnd().Split(/*';', */'\n');                
            for (int i = 1; i < lines.Length; i++)
            {                    
                Console.WriteLine($"String no {i} is : {lines[i-1]}");
            }                
        }

有了这个，我得到了台词，但在那之后我就卡住了。我是编码新手，所以任何帮助将不胜感激:)

Answer 1

这里有一些代码可以帮助您下车。

工作样本：

https://dotnetfiddle.net/L37Gjr

它首先将数据解析为一个单独的对象。然后将其用于构建 m-ary 树或连接节点的层次结构。（一个节点引用了 0 个或多个子节点）。

https://en.wikipedia.org/wiki/M-ary_tree

然后树遍历（如果需要了解更多，请使用google）插入并打印输出，但是还是有问题。它现在使用级别顺序遍历来打印，但是会出现错误：

Found root:1 - Company
Found root:10 - References
-------------------
1 - Company
    2 - About Us
    3 - Mission
        4 - Team
10 - References
    6 - Client 1
    5 - Client 2

如您所见，它在错误的级别上打印了 4 - Team。我会留给你来修复它（因为我运行没时间），如果没有，我希望我能给你很多想法让你自己去研究。

// sample for  by sommmen

using System;
using System.Collections;
using System.Linq;
using System.Collections.Generic;

public class Program
{
    public class Node<T>
    {
        public T Data {get;set;}    
        public List<Node<T>> Children { get; set;}

        public Node()
        {
            Children = new List<Node<T>>();
        }

        // Tree traversal in level order
         public List<Node<T>> LevelOrder()
        {
            List<Node<T>> list = new List<Node<T>>();
            Queue<Node<T>> queue = new Queue<Node<T>>();
            queue.Enqueue(this);
            while(queue.Count != 0)
            {               
                Node<T> temp = queue.Dequeue();
                foreach (Node<T> child in temp.Children)
                    queue.Enqueue(child);
                list.Add(temp);
            }
            return list;
        }

        public List<Node<T>> PreOrder()
        {
            List<Node<T>> list = new List<Node<T>>();
            list.Add(this);
            foreach (Node<T> child in Children)
                list.AddRange(child.PreOrder());
            return list;
        }

        public List<Node<T>> PostOrder()
        {
            List<Node<T>> list = new List<Node<T>>();
            foreach (Node<T> child in Children)
                list.AddRange(child.PreOrder());
            list.Add(this);
            return list;
        }


    }

    public class Entity
    {
        public int id   {get;set;}
        public string menuName {get;set;}
        public int? parentID {get;set;}
        public bool isHidden {get;set;}
        public string linkURL  {get;set;}
    }

    public static void Main()
    {
        var data = @"ID;MenuName;ParentID;isHidden;LinkURL
1;Company;NULL;False;/company
2;About Us;1;False;/company/aboutus
3;Mission;1;False;/company/mission
4;Team;2;False;/company/aboutus/team
5;Client 2;10;False;/references/client2
6;Client 1;10;False;/references/client1
7;Client 4;10;True;/references/client4
8;Client 5;10;True;/references/client5
10;References;NULL;False;/references";

        var lines = data.Split('\n');

        var rootNodes = new List<Node<Entity>>();
        var childItems = new List<Entity>();

        // Parse the data to entities
        // Items without a parent are used as rootnodes to build a tree
        foreach(var row in lines.Skip(1))
        {           
            var columns = row.Split(';');

            var id       = Convert.ToInt32(columns[0]);
            var menuName = columns[1];
            var parentID = ToNullableInt(columns[2]);
            var isHidden = Convert.ToBoolean(columns[3]);
            var linkURL  = columns[4];

            var entity = new Entity()
                              {
                                id = id,
                                  menuName = menuName,
                                  parentID = parentID,
                                  isHidden = isHidden,
                                  linkURL = linkURL
                              };

            if(parentID == null)
            {
                Console.WriteLine("Found root:" + entity.id + " - " + entity.menuName);

                rootNodes.Add(new Node<Entity>()
                              {
                                  Data = entity
                              });
            }
            else
            {
                childItems.Add(entity); 
            }
        }

        // Add the childElements to their appropriate rootnode

        foreach(var rootNode in rootNodes)
        {
            foreach(var childItem in childItems.OrderBy(a=>a.parentID).ThenBy(b=>b.menuName))
            {
                var newNode = new Node<Entity>()
                {
                    Data = childItem
                };

                Insert(rootNode, newNode);
            }
        }

        Console.WriteLine("-------------------");

        foreach(var rootNode in rootNodes)
        {
            var indent = 0;
            var previous = rootNode;
            foreach(var node in rootNode.LevelOrder())
            {
                if(node.Data.isHidden) continue;

                if(previous.Data.parentID != node.Data.parentID)
                    indent++;

                for(var i = 0; i < indent; i++)
                    Console.Write("\t");

                Console.WriteLine(node.Data.id + " - " + node.Data.menuName);
                previous = node;
            }
        }
    }

    public static void Insert(Node<Entity> rootNode, Node<Entity> targetNode)
    {
        foreach(var current in rootNode.LevelOrder())
        {
            if(current.Data.id == targetNode.Data.parentID)
            {
                current.Children.Add(targetNode);   
                return;
            }
        }
    }

    public static int? ToNullableInt(string s)
    {
        int i;
        if (int.TryParse(s, out i)) return i;
        return null;
    }
}

读取 csv 文件和 return 缩进菜单 c#

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