html xmlns="http://www.w3.org/1999/xhtml">
head runat="server">
title>/title>
/head>
body>
form id="form1" runat="server">
div>
asp:DropDownList runat="server" ID="ddlType">
/asp:DropDownList>
asp:Button runat="server" ID="btnSort" onclick="btnSort_Click" Text="排序" />
/div>
/form>
/body>
/html>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text.RegularExpressions;
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
ddlType.Items.Add(new ListItem("--请选择--"));
ddlType.Items.Add(new ListItem("2_bb"));
ddlType.Items.Add(new ListItem("1_aa"));
ddlType.Items.Add(new ListItem("4_ee"));
ddlType.Items.Add(new ListItem("3_dd"));
}
}
protected void btnSort_Click(object sender, EventArgs e)
{
DropDownListBubbleSort(ddlType);
//DropDownListSelectionSort(ddlType);
}
/// summary>
/// 冒泡排序
/// /summary>
/// param name="ddl">/param>
public void DropDownListBubbleSort(DropDownList ddl)
{
ListItem listItem = new ListItem();
for (int i = 0; i ddl.Items.Count; i++)
{
for (int j = i + 1; j ddl.Items.Count; j++)
{
int firstVal = 0, nextVal = 0;
int.TryParse(Regex.Replace(ddl.Items[i].Text, @"\D", @"", RegexOptions.IgnoreCase), out firstVal);
int.TryParse(Regex.Replace(ddl.Items[j].Text, @"\D", @"", RegexOptions.IgnoreCase), out nextVal);
if (firstVal == 0 || nextVal == 0)
continue;
if (firstVal > nextVal)
{
listItem = ddl.Items[j];
ddl.Items.Remove(ddl.Items[j]);
ddl.Items.Insert(i, listItem);
}
}
}
}
/// summary>
/// 选择排序
/// /summary>
/// param name="ddl">/param>
public void DropDownListSelectionSort(DropDownList ddl)
{
ListItem listItem = new ListItem();
int length = ddl.Items.Count;
for (int i = 0; i length; i++)
{
int min = 0;
int.TryParse(Regex.Replace(ddl.Items[i].Text, @"\D", @"", RegexOptions.IgnoreCase), out min);
if (min == 0)
continue;
int minIndex = i;
for (int j = i + 1; j length; j++)
{
int nextVal = 0;
int.TryParse(Regex.Replace(ddl.Items[j].Text, @"\D", @"", RegexOptions.IgnoreCase), out nextVal);
if (nextVal == 0)
continue;
if (min > nextVal)
{
min = nextVal;
minIndex = j;
}
}
if (minIndex != i)
{
listItem = ddl.Items[minIndex];
ddl.Items.Remove(ddl.Items[minIndex]);
ddl.Items.Insert(i, listItem);
}
}
}
}