网上的例子大都是静态的，已经写好的关键字，不能很好的满足用户的需求，所以需要从数据库查找到关键字，并显示出来。
效果如下：
首先，前台代码很简单，就是页面加载完执行jquery。
<script type="text/javascript">
function dropTip(){
$("input[id*=SearchBox]").bigAutocomplete({
width:155 //可以根据搜索框的大小自定义
});
}
$(document).ready(function() {
dropTip();
});
</script>
<asp:TextBox ID="SearchBox" runat="server" AutoCompleteType="Disabled" OnTextChanged="Search"/>
AutoCompleteType = "Disabled"是避免浏览器自动弹出提示。
jquery必不可少。dropTip.js代码如下：
(function($){
var bigAutocomplete = new function(){
this.currentInputText = null;//目前获得光标的输入框（解决一个页面多个输入框绑定自动补全功能）
this.functionalKeyArray = [9,20,13,16,17,18,91,92,93,45,36,33,34,35,37,39,112,113,114,115,116,117,118,119,120,121,122,123,144,19,145,40,38,27];//键盘上功能键键值数组
this.holdText = null;//输入框中原始输入的内容
//初始化插入自动补全div，并在document注册mousedown，点击非div区域隐藏div
this.init = function(){
$("body").append("<div id='bigAutocompleteContent' class='bigautocomplete-layout'></div>");
$(document).bind('mousedown',function(event){
var $target = $(event.target);
if((!($target.parents().andSelf().is('#bigAutocompleteContent'))) && (!$target.is(bigAutocomplete.currentInputText))){
bigAutocomplete.hideAutocomplete();
}
})
//鼠标悬停时选中当前行
$("#bigAutocompleteContent").delegate("tr", "mouseover", function() {
$("#bigAutocompleteContent tr").removeClass("ct");
$(this).addClass("ct");
}).delegate("tr", "mouseout", function() {
$("#bigAutocompleteContent tr").removeClass("ct");
});
//单击选中行后，选中行内容设置到输入框中，并执行callback函数
$("#bigAutocompleteContent").delegate("tr", "click", function() {
bigAutocomplete.currentInputText.val( $(this).find("div:last").html());
var callback_ = bigAutocomplete.currentInputText.data("config").callback;
if($("#bigAutocompleteContent").css("display") != "none" && callback_ && $.isFunction(callback_)){
callback_($(this).data("jsonData"));
}
bigAutocomplete.hideAutocomplete();
});
}
var res;
var $searchInput = $("input[id*=SearchBox]");
function ajax_request(){
$.ajax({
url:"../MasterPage/Handler/GetTipHandler.ashx", //服务器的地址
data:{'searchtext':$("input[id*=SearchBox]").val()}, //参数
dataType:'json', //返回数据类型
type:'POST', //请求类型
async: false,
success:function(data){
res = data;
}
});
}
this.autocomplete = function(param){
if($("body").length > 0 && $("#bigAutocompleteContent").length <= 0){
bigAutocomplete.init();//初始化信息
}
var $this = $(this);//为绑定自动补全功能的输入框jquery对象
var $bigAutocompleteContent = $("#bigAutocompleteContent");
//输入框keydown事件
$this.keydown(function(event) {
switch (event.keyCode) {
case 40://向下键
if($bigAutocompleteContent.css("display") == "none")return;
var $nextSiblingTr = $bigAutocompleteContent.find(".ct");
if($nextSiblingTr.length <= 0){//没有选中行时，选中第一行
$nextSiblingTr = $bigAutocompleteContent.find("tr:first");
}else{
$nextSiblingTr = $nextSiblingTr.next();
}
$bigAutocompleteContent.find("tr").removeClass("ct");
if($nextSiblingTr.length > 0){//有下一行时（不是最后一行）
$nextSiblingTr.addClass("ct");//选中的行加背景
$this.val($nextSiblingTr.find("div:last").html());//选中行内容设置到输入框中
//div滚动到选中的行,jquery-1.6.1 $nextSiblingTr.offset().top 有bug，数值有问题
$bigAutocompleteContent.scrollTop($nextSiblingTr[0].offsetTop - $bigAutocompleteContent.height() + $nextSiblingTr.height() );
}else{
$this.val(bigAutocomplete.holdText);//输入框显示用户原始输入的值
}
break;
case 38://向上键
if($bigAutocompleteContent.css("display") == "none")return;
var $previousSiblingTr = $bigAutocompleteContent.find(".ct");
if($previousSiblingTr.length <= 0){//没有选中行时，选中最后一行行
$previousSiblingTr = $bigAutocompleteContent.find("tr:last");
}else{
$previousSiblingTr = $previousSiblingTr.prev();
}
$bigAutocompleteContent.find("tr").removeClass("ct");
if($previousSiblingTr.length > 0){//有上一行时（不是第一行）
$previousSiblingTr.addClass("ct");//选中的行加背景
$this.val($previousSiblingTr.find("div:last").html());//选中行内容设置到输入框中
//div滚动到选中的行,jquery-1.6.1 $$previousSiblingTr.offset().top 有bug，数值有问题
$bigAutocompleteContent.scrollTop($previousSiblingTr[0].offsetTop - $bigAutocompleteContent.height() + $previousSiblingTr.height());
}else{
$this.val(bigAutocomplete.holdText);//输入框显示用户原始输入的值
}
break;
case 27://ESC键隐藏下拉框
bigAutocomplete.hideAutocomplete();
break;
}
});
//输入框keyup事件
$this.keyup(function(event) {
var k = event.keyCode;
var ctrl = event.ctrlKey;
var isFunctionalKey = false;//按下的键是否是功能键
var timeoutid;
for(var i=0;i<bigAutocomplete.functionalKeyArray.length;i++){
if(k == bigAutocomplete.functionalKeyArray[i]){
isFunctionalKey = true;
break;
}
}
//字母数字，退格，空格
if(event.keyCode > 40 || event.keyCode == 8 || event.keyCode ==32) {
clearTimeout(timeoutid);
ajax_request();
this.config = {
//width:下拉框的宽度，默认使用输入框宽度
width:$this.outerWidth() - 2,
//url：格式url:""用来ajax后台获取数据，返回的数据格式为data参数一样
url:null,
/*data：格式{data:[{title:null,result:{}},{title:null,result:{}}]}
url和data参数只有一个生效，data优先*/
data:res,
//callback：选中行后按回车或单击时回调的函数
callback:null};
$.extend(this.config,param);
//alert(res);
$this.data("config",this.config);
}
//k键值不是功能键或是ctrl+c、ctrl+x时才触发自动补全功能
if(!isFunctionalKey && (!ctrl || (ctrl && k == 67) || (ctrl && k == 88)) ){
var config = $this.data("config");
var offset = $this.offset();
$bigAutocompleteContent.width(config.width);
var h = $this.outerHeight() - 1;
$bigAutocompleteContent.css({"top":offset.top + h,"left":offset.left});
var data = config.data;
var url = config.url;
var keyword_ = $.trim($this.val());
if(keyword_ == null || keyword_ == ""){
bigAutocomplete.hideAutocomplete();
return;
}
if(data != null && $.isArray(data) ){
var data_ = new Array();
for(var i=0;i<data.length;i++){
if(data[i].title.indexOf(keyword_) > -1){
data_.push(data[i]);
}
}
makeContAndShow(data_);
}else if(url != null && url != ""){//ajax请求数据
$.post(url,{keyword:keyword_},function(result){
makeContAndShow(result.data)
},"json")
}
bigAutocomplete.holdText = $this.val();
}
//回车键
if(k == 13){
var callback_ = $this.data("config").callback;
if($bigAutocompleteContent.css("display") != "none"){
if(callback_ && $.isFunction(callback_)){
callback_($bigAutocompleteContent.find(".ct").data("jsonData"));
}
$bigAutocompleteContent.hide();
}
}
});
//组装下拉框html内容并显示
function makeContAndShow(data_){
if(data_ == null || data_.length <=0 ){
return;
}
var cont = "<table><tbody>";
for(var i=0;i<data_.length;i++){
cont += "<tr><td><div>" + data_[i].title + "</div></td></tr>"
}
cont += "</tbody></table>";
$bigAutocompleteContent.html(cont);
$bigAutocompleteContent.show();
//每行tr绑定数据，返回给回调函数
$bigAutocompleteContent.find("tr").each(function(index){
$(this).data("jsonData",data_[index]);
})
}
//输入框focus事件
$this.focus(function(){
bigAutocomplete.currentInputText = $this;
});
}
//隐藏下拉框
this.hideAutocomplete = function(){
var $bigAutocompleteContent = $("#bigAutocompleteContent");
if($bigAutocompleteContent.css("display") != "none"){
$bigAutocompleteContent.find("tr").removeClass("ct");
$bigAutocompleteContent.hide();
}
}
};
$.fn.bigAutocomplete = bigAutocomplete.autocomplete;
})(jQuery)
后台，ajax访问控制器，从数据库获得开头匹配用户输入的关键字，大概思想就是：如果一条记录中有一个字段是以keyword开头的，就将整个记录放入数据集中，并返回。在控制器handler中，访问数据集的表中的每一单元格，如果是以keyword开头的，就放入字符串数组arraywords中，完了之后arraywords可能会有重复值，就将不重复的字符串放入listString字符串数组中。最后将listString字符串数组中的每一个元素转换成json格式，并返回。：
public class GetTipHandler : IHttpHandler {
public void ProcessRequest(HttpContext context)
{
context.Response.Clear();
context.Response.Buffer = true;
context.Response.ContentType = "application/json";
context.Response.ContentEncoding.GetBytes("utf-8");
String json = "";
List<string> arraywords = new List<string>();
List<string> listString = new List<string>();
String[] words = {};
// String[] words = { "abc", "acc" };
DataSet g_ds = new DataSet();
String key = "";
int i = 0;
if (context.Request.Params["searchtext"] != "" && context.Request.Params["searchtext"] != null)
{
key = context.Request.Params["searchtext"];
try
{
g_ds = DynamicManager.GetDropTip(key);
foreach (DataRow dr in g_ds.Tables[0].Rows)
{
if (arraywords.Count > 40)
{
break;
}
if (dr["名称"].ToString().StartsWith(key))
{
arraywords.Add(dr["名称"].ToString());
}
if (dr["型号"].ToString().StartsWith(key))
{
arraywords.Add(dr["型号"].ToString());
}
if (dr["物料编码"].ToString().StartsWith(key))
{
arraywords.Add(dr["物料编码"].ToString());
}
if (dr["物料编码8"].ToString().StartsWith(key))
{
arraywords.Add(dr["物料编码8"].ToString());
}
}
//取出不重复的元素
foreach (string eachString in arraywords)
{
if (!listString.Contains(eachString))
listString.Add(eachString);
}
words = listString.ToArray();
}
catch (DcException dc)
{
ShowMessage(dc);
}
catch (Exception ex)
{
ShowMessage(new DcException("系统错误", ex));
}
if (key.Length != 0)
{
json = "[";
for (i = 0; i < words.Length; i++)
{
json +="{\"title\":\"" + words[i] + "\"}" + ",";
}
json = json.Substring(0, json.Length - 1 > 0 ? json.Length - 1 : 1);
json += "]";
}
}
context.Response.ContentEncoding = Encoding.UTF8;
context.Response.Write(json);//用到了Newtonsoft.dll 转化成Json格式
context.Response.Flush();
context.Response.End();
}
public bool IsReusable {
get {
return false;
}
}
protected virtual void ShowMessage(DcException dex)
{
}
}