泛型的排序问题
在实际应用中，遇到需要对泛型集合进行排序，感觉有点意思，给大家分享下。（代码粘贴到工程中改个namespace就可以用了）
VB.NET示例
HTML源码：
<%@ Page Language="vb" AutoEventWireup="false" Codebehind="ListSort.aspx.vb" Inherits="Saas.Demo.Report.ListSort" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>无标题页</title>
</head>
<body>
<form id="form1" runat="server">
<asp:DropDownList ID="CBOsortproperty" runat="server">
<asp:ListItem Selected="True" Text="Birth" Value="2"></asp:ListItem>
<asp:ListItem Text="ID" Value="0"></asp:ListItem>
<asp:ListItem Text="Name" Value="1"></asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="CBOsortorder" runat="server">
<asp:ListItem Selected="True" Text="降序" Value="1"></asp:ListItem>
<asp:ListItem Text="升序" Value="0"></asp:ListItem>
</asp:DropDownList>
<div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:BoundField DataField="ID" HeaderText="ID" />
<asp:BoundField DataField="Name" HeaderText="Name" />
<asp:BoundField DataField="Birth" HeaderText="Birth" />
</Columns>
</asp:GridView>
</div>
<asp:Button ID="Button1" runat="server" Text="排序" />
<asp:Button ID="Button2" runat="server" Text="恢复" />
</form>
</body>
</html>
Code Behind：
Imports System.Collections
Partial Public Class ListSort
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim lst As New List(Of Info)
lst.Add(New Info(1, "Tim", "1975-11-20"))
lst.Add(New Info(3, "Bob", "1978-11-20"))
lst.Add(New Info(2, "Ben", "2005-11-20"))
lst.Add(New Info(5, "Alston", "1995-11-20"))
lst.Add(New Info(4, "Thoms", "2001-11-20"))
Me.GridView1.DataSource = lst
Me.GridView1.DataBind()
End Sub
''' <summary>
''' 排序
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Protected Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim lst As New List(Of Info)
lst.Add(New Info(1, "Tim", "1975-11-20"))
lst.Add(New Info(3, "Bob", "1978-11-20"))
lst.Add(New Info(2, "Ben", "2005-11-20"))
lst.Add(New Info(5, "Alston", "1995-11-20"))
lst.Add(New Info(4, "Thoms", "2001-11-20"))
Dim c As CompareType
Select Case CBOsortproperty.SelectedValue
Case "2"
c = New CompareType(CompareType.CompareType.Birth)
Case "0"
c = New CompareType(CompareType.CompareType.ID)
Case "1"
c = New CompareType(CompareType.CompareType.Name)
Case Else
c = New CompareType(CompareType.CompareType.Birth)
End Select
lst.Sort(c)
If CBOsortorder.SelectedValue.Equals("1") Then
lst.Reverse()
End If
Me.GridView1.DataSource = lst
Me.GridView1.DataBind()
End Sub
''' <summary>
''' 恢复
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Protected Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim lst As New List(Of Info)
lst.Add(New Info(1, "Tim", "1975-11-20"))
lst.Add(New Info(3, "Bob", "1978-11-20"))
lst.Add(New Info(2, "Ben", "2005-11-20"))
lst.Add(New Info(5, "Alston", "1995-11-20"))
lst.Add(New Info(4, "Thoms", "2001-11-20"))
Me.GridView1.DataSource = lst
Me.GridView1.DataBind()
End Sub
Public Class Info
Public Sub New(ByVal i As Integer, ByVal n As String, ByVal b As DateTime)
Me.ID = i
Me.Name = n
Me.Birth = b
End Sub
Private _id As Integer
Private _name As String
Private _birth As DateTime
Public Property ID() As Integer
Get
Return _id
End Get
Set(ByVal value As Integer)
_id = value
End Set
End Property
Public Property Name() As String
Get
Return _name
End Get
Set(ByVal value As String)
_name = value
End Set
End Property
Public Property Birth() As DateTime
Get
Return _birth
End Get
Set(ByVal value As DateTime)
_birth = value
End Set
End Property
''' <summary>
''' 按指定属性比较的函数
''' </summary>
''' <param name="x">比较对象</param>
''' <param name="y">比较对象</param>
''' <param name="type">属性</param>
''' <returns>1:x>y;0:x=y;-1:y>x</returns>
''' <remarks>静态函数Shared Shadows Function</remarks>
Public Shared Shadows Function CompareByType(ByVal x As Info, ByVal y As Info, ByVal type As CompareType.CompareType) As Integer
Select Case type
Case CompareType.CompareType.ID
Return x.ID.CompareTo(y.ID)
Case CompareType.CompareType.Name
Return x.Name.CompareTo(y.Name)
Case CompareType.CompareType.Birth
Return x.Birth.CompareTo(y.Birth)
End Select
End Function
End Class
Class CompareType
Implements IComparer(Of Info) '继承比较器接口IComparer
Public Sub New()
Me.ComType = CompareType.Birth
End Sub
Public Sub New(ByVal ct As CompareType)
Me.ComType = ct
End Sub
Public Enum CompareType
ID
Name
Birth
End Enum
Private _comType As CompareType
Public Property ComType() As CompareType
Get
Return _comType
End Get
Set(ByVal value As CompareType)
_comType = value
End Set
End Property
''' <summary>
''' 设定排序属性
''' </summary>
''' <param name="ct"></param>
''' <remarks></remarks>
Public Sub SetCompareType(ByVal ct As CompareType)
Me.ComType = ct
End Sub
''' <summary>
''' 比较函数
''' </summary>
''' <param name="x">比较对象</param>
''' <param name="y">比较对象</param>
''' <returns>1:x>y;0:x=y;-1:y>x</returns>
''' <remarks>实现接口的Compare方法</remarks>
Public Function Compare(ByVal x As Info, ByVal y As Info) As Integer Implements System.Collections.Generic.IComparer(Of Info).Compare
If x Is Nothing Then
If y Is Nothing Then
Return 0
Else
Return -1
End If
ElseIf y Is Nothing Then
Return 1
Else
Return Info.CompareByType(x, y, ComType)
End If
End Function
End Class
End Class
C#.NET示例
HTML源码：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ListSort.aspx.cs" Inherits="CSharpTest.ListSort" %>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>泛型排序</title>
</head>
<body>
<form id="form1" runat="server">
<asp:DropDownList ID="CBOsortproperty" runat="server">
<asp:ListItem Selected="True" Text="Birthday" Value="2"></asp:ListItem>
<asp:ListItem Text="ID" Value="0"></asp:ListItem>
<asp:ListItem Text="Name" Value="1"></asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="CBOsortorder" runat="server">
<asp:ListItem Selected="True" Text="降序" Value="1"></asp:ListItem>
<asp:ListItem Text="升序" Value="0"></asp:ListItem>
</asp:DropDownList>
<div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:BoundField DataField="ID" HeaderText="ID" />
<asp:BoundField DataField="Name" HeaderText="Name" />
<asp:BoundField DataField="Birthday" HeaderText="Birthday" />
</Columns>
</asp:GridView>
</div>
<asp:Button ID="Button1" runat="server" Text="排序" OnClick="Button1_Click" />
<asp:Button ID="Button2" runat="server" Text="恢复" OnClick="Button2_Click" />
</form>
</body>
</html>
Code Behind:
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections.Generic;
namespace CSharpTest
{
public partial class ListSort : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
GridView1.DataSource = InitList();
GridView1.DataBind();
}
/// <summary>
/// 初始化泛型集合
/// </summary>
/// <returns></returns>
private List<Info> InitList()
{
List<Info> lst = new List<Info>();
lst.Add(new Info(2, "T", "1985"));
lst.Add(new Info(5, "B", "1856"));
lst.Add(new Info(1, "A", "1997"));
lst.Add(new Info(4, "Z", "2009"));
lst.Add(new Info(3, "G", "2000"));
return lst;
}
/// <summary>
/// 排序
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Button1_Click(object sender, EventArgs e)
{
List<Info> lst = InitList();
//创建比较器实例
CompareType c;
switch (CBOsortproperty.SelectedValue)
{
case "0":
c = new CompareType(CompareType.CompType.ID);
break;
case "1":
c = new CompareType(CompareType.CompType.Name);
break;
case "2":
c = new CompareType(CompareType.CompType.Birthday);
break;
default:
c = new CompareType(CompareType.CompType.Birthday);
break;
}
lst.Sort(c);
if (CBOsortorder.SelectedValue.Equals("1"))
{
lst.Reverse(); //泛型排序默认为升序,若要求降序排序,需调用此方法
}
GridView1.DataSource = lst;
GridView1.DataBind();
}
/// <summary>
/// 恢复
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Button2_Click(object sender, EventArgs e)
{
GridView1.DataSource = InitList();
GridView1.DataBind();
}
}
public class Info
{
//构造函数
public Info(int i,string n,string b)
{
ID = i;
Name = n;
Birthday = b;
}
//Property
private int _ID;
public int ID
{
get { return _ID; }
set { _ID = value; }
}
private string _Name;
public string Name
{
get { return _Name; }
set { _Name = value; }
}
private string _Birthday;
public string Birthday
{
get { return _Birthday; }
set { _Birthday = value; }
}
/// <summary>
/// 静态函数,实现比较功能,便于在类CompareType中调用
/// </summary>
/// <param name="x">比较对象</param>
/// <param name="y">比较对象</param>
/// <param name="type">排序属性(枚举类型)</param>
/// <returns>1:x>y;0:x==y;-1:y>x</returns>
public static int CompareByType(Info x,Info y,CompareType.CompType type)
{
switch (type)
{
case CompareType.CompType.ID:
return x.ID.CompareTo(y.ID);
case CompareType.CompType.Name:
return x.Name.CompareTo(y.Name);
case CompareType.CompType.Birthday:
return x.Birthday.CompareTo(y.Birthday);
default:
return 0;
}
}
}
/// <summary>
/// 实现比较器接口IComparer
/// </summary>
public class CompareType:IComparer<Info>
{
public CompareType()
{
ComType = CompareType.CompType.Birthday;
}
public CompareType(CompType c)
{
ComType = c;
}
public enum CompType
{
ID,
Name,
Birthday
}
private CompType _ComType;
public CompType ComType
{
get { return _ComType; }
set { _ComType = value; }
}
/// <summary>
/// 实现IComparer.Compare()
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <returns></returns>
public int Compare(Info x, Info y)
{
if (x == null)
{
if (y == null)
{
return 0;
}
else
{
return -1;
}
}
else if (y == null)
{
return 1;
}
else
{
return Info.CompareByType(x,y,ComType); //调用类Info的静态函数CompareByType
}
}
}
}