有时候刚好表中没有可以排序的字段，又不想修改表结构，但它的项文本有序号，这时就可以用这方法排序，例如:
测试页Default2.aspx：
<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>
Default2.aspx.cs：
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);
}
}
}
}