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  • linq to DataTable 排序

    using System;
    using System.Collections.Generic;
    using System.Data;
    using System.Linq;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    
    namespace ty.net.test.Sort
    {
        public partial class WebForm1 : System.Web.UI.Page
        {
            protected void Page_Load(object sender, EventArgs e)
            {
    
            }
    
            DataTable test()
            {
                DataTable dtA = new DataTable();
                dtA.Columns.Add("id", typeof(int));
                dtA.Columns.Add("goodNum", typeof(double));
                dtA.Columns.Add("generalNum", typeof(double));
                dtA.Columns.Add("badNum", typeof(double));
    
                //dtA.Rows.Add(1, "20", "30", "50");  
                //dtA.Rows.Add(2, "90", "3", "2");  
                dtA.Rows.Add(3, "11", "5", "10");
                dtA.Rows.Add(4, "10", "32", "-2");
                dtA.Rows.Add(5, "66", "55", "44");
                return dtA;
            }
    
            protected void Button1_Click(object sender, EventArgs e)
            {
                //升序
                DataTable dt = LinqSortDataTable2(test(), "badNum");
                GridView1.DataSource = dt;
                GridView1.DataBind();
            }
    
    
            protected void Button2_Click(object sender, EventArgs e)
            {
                //降序
                DataTable dt = LinqSortDataTable(test(), 3);
                GridView1.DataSource = dt;
                GridView1.DataBind();
            }
    
    
            /// <summary>
            /// 对datatable按照某一列进行linq排序,因为dataview自带的排序处理不了负数的排序
            /// </summary>
            /// <param name="tmpDt">需要排序的datatable</param>
            /// <param name="sortId">排序的列序号,从0开始</param>
            /// <returns></returns>
            protected DataTable LinqSortDataTable(DataTable tmpDt, int sortId)
            {
                DataView dv = tmpDt.DefaultView;
                var query = (from item in tmpDt.AsEnumerable()
                             orderby Convert.ToInt32(item[sortId]) descending
                             select item);
                //重新排序
                dv = query.AsDataView();
                return dv.ToTable();
            }
    
    
            /// <summary>
            /// 对datatable按照某一列进行linq排序
            /// </summary>
            /// <param name="tmpDt">需要排序的datatable</param>
            /// <param name="sortId">排序的列序号,从0开始</param>
            /// <returns></returns>
            protected DataTable LinqSortDataTable2(DataTable tmpDt, string columnName)
            {
                DataView dv = tmpDt.DefaultView;
                var query = (from item in tmpDt.AsEnumerable()
                             orderby item[columnName] 
                             select item);
                //重新排序
                dv = query.AsDataView();
                return dv.ToTable();
            }
        }
    
    }
    
    <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="ty.net.test.Sort.WebForm1" %>
    
    <!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>
            <asp:Button ID="Button1" runat="server" Text="升序" OnClick="Button1_Click" />
             <asp:Button ID="Button2" runat="server" Text="降序" OnClick="Button2_Click" />
            <asp:GridView ID="GridView1" runat="server"></asp:GridView>
        </div>
        </form>
    </body>
    </html>
    

     

    可能你遇到这个问题, AsEnumerable方法找不到?

    添加引用了System.Data.DataSetExtensions   搞定!!!!

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  • 原文地址:https://www.cnblogs.com/suntanyong88/p/4544470.html
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