[ASP.NET]利用List的Sort()、Find()、FindAll()、Exist()來解決一些問題
轉載自：http://www.dotblogs.com.tw/puma/archive/2009/05/28/asp.net-generic-list-sort-find-findall-exsit.aspx
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); |
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} |
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} |
執行結果：
參考網址：
http://blogs.msdn.com/kcwalina/archive/2004/06/22/162533.aspx
http://www.dotblogs.com.tw/chhuang/archive/2008/05/08/3908.aspx