请问这样的数据源怎么用代码实现拆分？

Z时代
2024-01-10
分类：IT

演示代码链接： https://pan.baidu.com/s/1v9LBRDxdRq-vTj-ru7tilA

提取码：c553

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DataSplitDemo.aspx.cs" Inherits="Develop_BBS_DataSplitDemo" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <h4>数据源：每个种类各占一行</h4>
            <asp:GridView runat="server" ID="gvSource"></asp:GridView>
            <h4>目的：按数量合并，各自编号加起来数量等于数据源的各自的数量</h4>
            <asp:GridView runat="server" ID="gvResult"></asp:GridView>
<pre>
说明：id为1001的Count为1（只有第一行存在）；
      id为1002的Count为2，1（第一行）+1（第二行）；
      id为1003的Count为5，1（第一行）+1（第二行）+3（第三行）；
</pre>
            <h4>问题：如何用代码把数据源转为目的那样的结果？</h4>
        </div>
    </form>
</body>
</html>

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class Develop_BBS_DataSplitDemo : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        var dtSource = new DataTable();
        dtSource.Columns.Add("Id", typeof(int));
        dtSource.Columns.Add("Name", typeof(string));
        dtSource.Columns.Add("Count", typeof(int));
        var drNew = dtSource.NewRow();
        drNew["Id"] = 1001;
        drNew["Name"] = "苹果";
        drNew["Count"] = 1;
        dtSource.Rows.Add(drNew);
        drNew = dtSource.NewRow();
        drNew["Id"] = 1002;
        drNew["Name"] = "香蕉";
        drNew["Count"] = 2;
        dtSource.Rows.Add(drNew);
        drNew = dtSource.NewRow();
        drNew["Id"] = 1003;
        drNew["Name"] = "橙子";
        drNew["Count"] = 5;
        dtSource.Rows.Add(drNew);
        //...实际为动态行数
        this.gvSource.DataSource = dtSource;
        this.gvSource.DataBind();
        var dtResult = new DataTable();
        dtResult.Columns.Add("Ids", typeof(string));
        dtResult.Columns.Add("Names", typeof(string));
        dtResult.Columns.Add("Count", typeof(int));
        var drResult = dtResult.NewRow();
        drResult["Ids"] = "1001,1002,1003";
        drResult["Names"] = "苹果,香蕉,橙子";
        drResult["Count"] = 1;
        dtResult.Rows.Add(drResult);
        drResult = dtResult.NewRow();
        drResult["Ids"] = "1002,1003";
        drResult["Names"] = "香蕉,橙子";
        drResult["Count"] = 1;
        dtResult.Rows.Add(drResult);
        drResult = dtResult.NewRow();
        drResult["Ids"] = "1003";
        drResult["Names"] = "橙子";
        drResult["Count"] = 3;
        dtResult.Rows.Add(drResult);
        this.gvResult.DataSource = dtResult;
        this.gvResult.DataBind();
    }}

回答：

{

class Program
{
    static void Main(string[] args)
    {
        //读取数据库表
        List<Frult> frults = new List<Frult>
        {
            new Frult{ Id = "1001", Name = "苹果", Count = 1 },
            new Frult{ Id = "1002", Name = "香蕉", Count = 2 },
            new Frult{ Id = "1003", Name = "橙子", Count = 5 },
        };
        List<Frult> frultsRs = new List<Frult>();
        while (true)
        {
            frults.RemoveAll(f => f.Count <= 0);
            if (frults.Count == 0) break;
            var doneIds = frults.Select(c => c.Id);
            string id = string.Join(',', doneIds);
            var frultGroup = frultsRs.FirstOrDefault(f => f.Id == id);
            if (frultGroup == null) frultsRs.Add(new Frult
            {
                Id = id,
                Name = string.Join(',', frults.Select(c => c.Name)),
                Count = 1
            });
            else
            {
                frultGroup.Count += 1;
            }
            frults.ForEach(f => f.Count -= 1);
        }
        foreach (var d in frultsRs)
        {
            Console.WriteLine(string.Format("{0}, {1}, {2}", d.Id, d.Name, d.Count));
        }
        Console.ReadKey();
    }
}
public class Frult
{
    public string Id { get; set; }
    public string Name { get; set; }
    public int Count { get; set; }}