<asp:ScriptManager ID="ScriptManager1" runat="server" />
<cc1:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" TargetControlID="TextBox1"
ServicePath="KeyFind.asmx" CompletionSetCount="10" MinimumPRefixLength="1" ServiceMethod="GetCompleteDepart">
</cc1:AutoCompleteExtender>
<asp:TextBox ID="TextBox1" runat="server" Width="352px" Height="27px"></asp:TextBox>

using System;
using System.Web;
using System.Collections;
using System.Web.Services;
using System.Web.Services.Protocols;
//引入空间
using System.Data;
using System.Data.OleDb;
using System.configuration;
/// <summary>
/// KeyFind 的摘要说明
/// </summary>
[WebService(namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
//添加服务脚本（必须添，否则程序不能正常运行）
[System.Web.Script.Services.ScriptService]
public class KeyFind : System.Web.Services.WebService
{
public KeyFind()
{
//如果使用设计的组件，请取消注释以下行
//Initializecomponent();
}
//定义数组保存获取的内容
private string[] autoCompleteWordList = null;
//两个参数“prefixText”表示用户输入的前缀，count表示返回的个数
[WebMethod]
public String[] GetCompleteDepart(string prefixText, int count)
{
///检测参数是否为空
if (string.IsNullOrEmpty(prefixText) == true || count <= 0) return null;
// 如果数组为空
if (autoCompleteWordList == null)
{
//读取数据库的内容
OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("Ex18_02.mdb"));
conn.OPEn();
OleDbDataAdapter da = new OleDbDataAdapter("select keyName From keyInfo where keyName like'" + prefixText + "%' order by keyName", conn);
DataSet ds = new DataSet();
da.Fill(ds);
//读取内容文件的数据到临时数组
string[] temp = new string[ds.Tables[0].Rows.Count];
int i = 0;
foreach (DataRow dr in ds.Tables[0].Rows)
{
temp[i] = dr["keyName"].ToString();
i++;
}
Array.Sort(temp, new CaseInsensitiveComparer());
//将临时数组的内容赋给返回数组
autoCompleteWordList = temp;
if (conn.state == ConnectionState.Open)
conn.Close();
}
//定位二叉树搜索的起点
int index = Array.BinarySeArch(autoCompleteWordList, prefixText, new CaseInsensitiveComparer());
if (index < 0)
{ //修正起点
index = ~index;
}
//搜索符合条件的数据
int matchCount = 0;
for (matchCount = 0; matchCount < count && matchCount + index < autoCompleteWordList.Length; matchCount++)
{ ///查看开头字符串相同的项
if (autoCompleteWordList[index + matchCount].StartsWith(prefixText, StringComparison.currentCultureIgnoreCase) == false)
{
break;
}
}
//处理搜索结果
string[] matchresultList = new string[matchCount];
if (matchCount > 0)
{ //复制搜索结果
Array.Copy(autoCompleteWordList, index, matchResultList, 0, matchCount);
}
return matchResultList;
}
}