下面的循环如何写

Question

本帖最后由 caozhy 于 2011-06-14 21:41:36 编辑

Answer 1

3张表就够了，类别、品牌、型号。品牌表里有一个字段表示类别id，型号表里有一个字段表示品牌id，应该够了

Answer 2

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;namespace ConsoleApplication1
{
    class Program
    {
        class Data
        {
            public int Level { get; set; }
            public string ID { get; set; }
            public string Name { get; set; }
            public List<Data> Childs { get; set; }
            public Data() { Childs = new List<Data>(); }            public Data this[string id]
            {
                get 
                {
                    if (ID == id) return this;
                    Data data = null;
                    if (Childs.Count > 0)
                    {
                        data = Childs.Where(x => x.ID == id).SingleOrDefault();
                        if (data == null)
                        {
                            foreach (var item in Childs)
                            {
                                data = item[id];
                                if (data != null) break;
                            }
                        }
                    }
                    return data;
                }
            }
            public override string ToString()
            {
                string TableChar = "";
                for (int i = 0; i < Level; i++) TableChar += "\t";
                StringBuilder sb = new StringBuilder();
                if (Childs.Count == 0)
                {
                    sb.Append(string.Format("{0}{{name:{1}}}", TableChar, Name));
                }
                else
                {
                    sb.AppendLine(string.Format("{0}{{name:{1}[", TableChar, Name));
                    for (int i = 0; i < Childs.Count; i++)
                    {
                        sb.AppendLine("\t" +
                            Childs[i].ToString() + ((i == Childs.Count - 1) ? "" : ","));
                    }
                    sb.Append(string.Format("\t{0}]}}", TableChar));
                }
                return sb.ToString();
            }
        }        static void Main(string[] args)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("id");
            dt.Columns.Add("name");
            dt.Rows.Add("01", "电脑");
            dt.Rows.Add("02", "手机");
            dt.Rows.Add("03", "电视机");
            dt.Rows.Add("0101", "联想");
            dt.Rows.Add("0102", "华硕");
            dt.Rows.Add("0103", "惠普");
            dt.Rows.Add("0201", "诺基亚");
            dt.Rows.Add("0202", "三星");
            dt.Rows.Add("0301", "夏普");
            dt.Rows.Add("0302", "海尔");
            dt.Rows.Add("020101", "N81");
            dt.Rows.Add("020102", "N95");
            var list = (from x
                       in dt.Rows.Cast<DataRow>()
                        group x by x["id"].ToString().Length into g
                        select new { Key = g.Key, Items = g.ToList() }).OrderBy(x => x.Key);
            List<Data> DataRoot = new List<Data>();
            list.ToList()
                .ForEach(x =>
                {
                    if (x.Key == 2)
                    {
                        x.Items.ForEach(y => DataRoot.Add(new Data()
                                                        {
                                                            ID = y["id"].ToString(),
                                                            Name = y["Name"].ToString(),
                                                            Level = x.Key / 2 - 1
                                                        }));
                    }
                    else
                    {
                        x.Items.ForEach(y =>
                        {
                            Data data = null;
                            foreach (var item in DataRoot)
                            {
                                data = item[y["id"].ToString().Substring(0, y["id"].ToString().Length - 2)];
                                if (data != null) break;
                            }
                            if (data != null)
                            {
                                data.Childs.Add(new Data()
                                    {
                                        ID = y["id"].ToString(),
                                        Name = y["Name"].ToString(),
                                        Level = x.Key / 2 - 1
                                    });
                            }
                        });
                    }
                });
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < DataRoot.Count; i++)
            { 
                sb.AppendLine(DataRoot[i].ToString());
            }
            string Result = sb.ToString();
            Console.WriteLine(Result);
        }
    }
}
{name:电脑[
                {name:联想},
                {name:华硕},
                {name:惠普}
        ]}
{name:手机[
                {name:诺基亚[
                        {name:N81},
                        {name:N95}
                ]},
                {name:三星}
        ]}
{name:电视机[
                {name:夏普},
                {name:海尔}
        ]}Press any key to continue . . .

Answer 3

太精彩了，收藏并研究。我一开始的思路是这样，类似数据库表操作，
自己Join自己如dt join dt按照条件 d2=>d2.Id.StartWith(d1.Id) && d2.Id != d1.Id
将结果存到一个新的dt中，列为 Id1 Id2 (Id2开头部分为Id1)，再用新的dt2 jion dt得到dt3（Id，Id2，Id3）
继续join直到Idn的值全部为null，比如对于只有三层的结构将得到这样的数据
01 0101 null null
01 0102 null null
01 0102 010201 null
01 0102 010202 null
01 0103 010301 01030101
01 0103 01030101 null
01 010201 null null
01 010202 null null
01 010301 null null
0102 010201 null null
0102 010202 null null
0103 010301 01030101 null
0103 01030101 null null移除重复项(当一行石林一行的子集)得到
01 0101
01 0102
01 0102 010201
01 0102 010202
01 0103 010301 01030101一种变相的树图表述，再加工输出结果。

Answer 4

呵呵，小修正下：using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;namespace ConsoleApplication1
{
    class Program
    {
        class Data
        {
            public int Level { get; set; }
            public string ID { get; set; }
            public string Name { get; set; }
            public List<Data> Childs { get; set; }
            public Data() { Childs = new List<Data>(); }            public Data this[string id]
            {
                get
                {
                    if (ID == id) return this;
                    Data data = null;
                    if (Childs.Count > 0)
                    {
                        data = Childs.Where(x => x.ID == id).SingleOrDefault();
                        if (data == null)
                        {
                            foreach (var item in Childs)
                            {
                                data = item[id];
                                if (data != null) break;
                            }
                        }
                    }
                    return data;
                }
            }
            public override string ToString()
            {
                string TableChar = "";
                for (int i = 0; i < Level; i++) TableChar += "\t";
                StringBuilder sb = new StringBuilder();
                if (Childs.Count == 0)
                {
                    sb.Append(string.Format("{0}{{name:{1}}}", TableChar, Name));
                }
                else
                {
                    sb.AppendLine(string.Format("{0}{{name:{1}[", TableChar, Name));
                    for (int i = 0; i < Childs.Count; i++)
                    {
                        sb.AppendLine("\t" +
                            Childs[i].ToString() + ((i == Childs.Count - 1) ? "" : ","));
                    }
                    sb.Append(string.Format("\t{0}]}}", TableChar));
                }
                return sb.ToString();
            }
        }        static void Main(string[] args)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("id");
            dt.Columns.Add("name");
            dt.Rows.Add("01", "电脑");
            dt.Rows.Add("02", "手机");
            dt.Rows.Add("03", "电视机");
            dt.Rows.Add("0101", "联想");
            dt.Rows.Add("0102", "华硕");
            dt.Rows.Add("0103", "惠普");
            dt.Rows.Add("0201", "诺基亚");
            dt.Rows.Add("0202", "三星");
            dt.Rows.Add("0301", "夏普");
            dt.Rows.Add("0302", "海尔");
            dt.Rows.Add("020101", "N81");
            dt.Rows.Add("020102", "N95");
            var list = (from x
                       in dt.Rows.Cast<DataRow>()
                        group x by x["id"].ToString().Length into g
                        select new { Key = g.Key, Items = g.ToList() }).OrderBy(x => x.Key);
            List<Data> DataRoot = new List<Data>();
            list.ToList()
                .ForEach(x =>
                {
                    if (x.Key == 2)
                    {
                        x.Items.ForEach(y => DataRoot.Add(new Data()
                        {
                            ID = y["id"].ToString(),
                            Name = y["Name"].ToString(),
                            Level = x.Key / 2 - 1
                        }));
                    }
                    else
                    {
                        x.Items.ForEach(y =>
                        {
                            Data data = null;
                            foreach (var item in DataRoot)
                            {
                                data = item[y["id"].ToString().Substring(0, y["id"].ToString().Length - 2)];
                                if (data != null) break;
                            }
                            if (data != null)
                            {
                                data.Childs.Add(new Data()
                                {
                                    ID = y["id"].ToString(),
                                    Name = y["Name"].ToString(),
                                    Level = x.Key / 2 - 1
                                });
                            }
                        });
                    }
                });
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < DataRoot.Count; i++)
            {
                sb.Append(DataRoot[i].ToString() + ((i == DataRoot.Count - 1) ? "" : ",\r\n"));
            }
            string Result = sb.ToString();
            Console.WriteLine(Result);
        }
    }
}