[ASP.NET]利用List的Sort()、Find()、FindAll()、Exist()來解決一些問題

最近寫案子常常用到List<T>,這個東西還真好用

因為它有下列東西：

List<T>.Sort() → 排序T

List<T>.Find() → 找出一個T

List<T>.FindAll() →找出多個T

List<T>.Exist() →判斷T是否存在

小弟就寫個範例介紹這些東西吧..

GenericList.aspx

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<%@ Page Language="C#" AutoEventWireup="true" CodeFile="GenericList.aspx.cs" Inherits="GenericList" %>

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

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<html xmlns="http://www.w3.org/1999/xhtml">

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<head runat="server">

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    <title>GenericList</title>

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</head>

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<body>

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    <form id="form1" runat="server">

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    <div>

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        原始資料：

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        <asp:GridView ID="GridView1" runat="server">

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        </asp:GridView>

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    </div>

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    </form>

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</body>

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</html>

GenericList.aspx.cs

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using System;

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using System.Collections.Generic;

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using System.Web;

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using System.Web.UI;

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using System.Web.UI.WebControls;

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public partial class GenericList : System.Web.UI.Page

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{

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    protected void Page_Load(object sender, EventArgs e)

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    {

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        List<Person> lstPerson = new List<Person>();

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        lstPerson.Add(new Person(1, "puma", 10));

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        lstPerson.Add(new Person(2, "F6 Team", 20));

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        lstPerson.Add(new Person(3, "ASP.NET", 30));

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        lstPerson.Add(new Person(4, "Dotblogs", 40));

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        //原始資料顯示在GridView上

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        this.GridView1.DataSource = lstPerson;

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        this.GridView1.DataBind();

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        //List<T>.Find()

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        //找出Name='puma'的Person

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        Response.Write("找出Name='puma'的Person→ ");

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        Response.Write(lstPerson.Find(delegate(Person p) { return p.Name == "puma"; }).ToString() + "<p>");

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        //List<T>.FindAll()

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        //找出Age>10的數目

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        Response.Write("找出Age>10的數目→ ");

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        Response.Write(lstPerson.FindAll(delegate(Person p) { return p.Age > 10; }).Count.ToString() + "<p>");

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        //List<T>.Exists()

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        //檢查Name='F6'是否存在

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        Response.Write("檢查Name='F6'是否存在→ ");

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        Response.Write(lstPerson.Exists(delegate(Person p) { return p.Name == "F6"; }).ToString() + "<p>");

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        //List<T>.Sort()

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        //依Name升冪排序

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        Response.Write("<p>依Name升冪排序↑<br/>");

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        lstPerson.Sort(delegate(Person p1, Person p2) { returnComparer<string>.Default.Compare(p1.Name, p2.Name); });

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        foreach (Person p in lstPerson)

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        {

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            Response.Write(p.ToString() + "<br/>");

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        }

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        //List<T>.Sort()

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        //依Name降冪排序

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        Response.Write("<p>依Name降冪排序↓<br/>");

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        lstPerson.Sort(delegate(Person p1, Person p2) { returnComparer<string>.Default.Compare(p2.Name, p1.Name); });

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        foreach (Person p in lstPerson)

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        {

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            Response.Write(p.ToString() + "<br/>");

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        }

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    }

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}

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public class Person

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{

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    private int _ID;

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    private string _Name;

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    private int _Age;

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    public Person(int ID, string Name, int Age)

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    {

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        _ID = ID;

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        _Name = Name;

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        _Age = Age;

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    }

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    public int ID

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    {

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        set { _ID = value; }

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        get { return _ID; }

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    }

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    public string Name

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    {

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        set { _Name = value; }

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        get { return _Name; }

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    }

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    public int Age

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    {

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        set { _Age = value; }

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        get { return _Age; }

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    }

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    public override string ToString()

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    {

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        return string.Format("ID：{0}，Name：{1}，Age：{2}", _ID, _Name, _Age);

}

102 }

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;
using System.Data;
using SqlServerHelper;
using LogisticsMODEL;
using LogisticsDAL;
using Untity;
using System.Text;
namespace LogisticsBLL
{

    public class B_Sys_Region : IB_Sys_Region
    {
        public static IList<M_Sys_Region> GetProvince()
        {
            return GetRegionList().FindAll(delegate(M_Sys_Region m) { return m.Parentid == 0; });
        }
        public static IList<M_Sys_Region> GetRegionList(int parentid)
        {
            return GetRegionList().FindAll(delegate(M_Sys_Region m) { return m.Parentid == parentid; });
        }
        /// <summary>
        /// 根据编码查询地区名称
        /// </summary>
        /// <param name="_Codeid"></param>
        /// <returns></returns>
        public static M_Sys_Region GetRegionModes(int _Codeid)
        {
            Dictionary<int, M_Sys_Region> d_Region = CacheHelper.GetCache(B_CacheKey.Sys_Region_Dictionary) as Dictionary<int, M_Sys_Region>;
            if (d_Region == null)
            {
                d_Region = new Dictionary<int, M_Sys_Region>();
                IList<M_Sys_Region> _RegionList = new B_Sys_Region().SelectDataWhere(null);
                foreach (M_Sys_Region sys_RegionModel in _RegionList)
                {
                    d_Region.Add(sys_RegionModel.Codeid.Value, sys_RegionModel);
                }
            }
            M_Sys_Region _M_Sys_Region = new M_Sys_Region();
            return d_Region.TryGetValue(_Codeid, out _M_Sys_Region) ? _M_Sys_Region : null;
        }

    /// <summary>
    /// 模糊搜索地区 返回地球对象和地区级别
    /// </summary>
    /// <param name="name">地区名称</param>
    /// <param name="lv">1表示省 2城市 3表示区县</param>
    /// <returns></returns>
        public static M_Sys_Region GetRegionLikeModel(string name,out int  lv) {
            lv = -1;
           const int Province = 2;//省的编号长度
           const int City = 4;//市的编号长度
           const int County = 6;//县区的编号长度

           M_Sys_Region _M_Sys_Region=GetRegionList().Find(delegate (M_Sys_Region m){ return  m.Name.IndexOf(name)>-1;  });
           if (_M_Sys_Region != null && _M_Sys_Region.Codeid != null)
           {
               switch (_M_Sys_Region.Codeid.Value.ToString().Length)
               {

                   case Province: lv = 1; break;
                   case City: lv = 2; break;
                   case County: lv = 3; break;
              }
           }
           return _M_Sys_Region;
        }

        public static List<M_Sys_Region> GetRegionList()
        {
            List<M_Sys_Region> syslist = CacheHelper.GetCache(B_CacheKey.Sys_Region) as List<M_Sys_Region>;
            if (syslist == null)
            {
                syslist = new B_Sys_Region().SelectDataWhere(null) as List<M_Sys_Region>;
                CacheHelper.SetCache(B_CacheKey.Sys_Region, syslist);
            }
            return syslist;
        }
    }
}