联动下拉框 jquery插件（三）

<select id="CategoryFirst" class="ld-select-1" name="CategoryFirst"><option value="">请选择大类</option></select>

<select id="CategorySecond" class="ld-select-1" name="CategorySecond"><option value="">请选择小类</option></select>[/code]

<script src="../Scripts/jquery-1.6.1.min.js" type="text/javascript"></script>

<script src="../Scripts/jQuery.LiveSelect.js" type="text/javascript"></script>
[/code]

$(".ld-select-1").ld({ ajaxOptions: { "url": "../Ajax/CategoryHandler.ashx" }, defaultParentId: 1,

style: { "width": 120}[/code]

});

if (context.Request.Params["CategoryParentID"] != null)

{
[/code]

sql = String.Format("SELECT CategoryId ,CategoryName  FROM B_Category

WHERE CategoryParentID='{0}'", context.Request.Params["CategoryParentID"]);

}

数据库 单表 id name parentidjson格式 同 前第一篇
[code]插件：

(function ($) {
$.fn.ld = function (options) {
var opts;
var DATA_NAME = "ld";
//返回API
if (typeof options == 'string') {
if (options == 'api') {
return $(this).data(DATA_NAME);
}
}
else {
var options = options || {};
//覆盖参数
opts = $.extend(true, {}, $.fn.ld.defaults, options);
}
if ($(this).size() > 0) {
var ld = new yijs.Ld(opts);
ld.$applyTo = $(this);
ld.render();
$(this).data(DATA_NAME, ld);
}
return $(this);
}
var yijs = yijs || {};
yijs.Ld = function (options) {
//参数
this.options = options;
//起作用的对象
this.$applyTo = this.options.applyTo && $(this.options.applyTo) || null;
//缓存前缀
this.cachePrefix = "data_";
//写入到选择框的option的样式名
this.OPTIONS_CLASS = "ld-option";
//缓存，为一个对象字面量。
this.cache = {};
}
yijs.Ld.prototype = {
/**
* 运行
* @return {Object} this
*/
render: function () {
var _that = this;
var _opts = this.options;
if (this.$applyTo != null && this.size() > 0) {
_opts.style != null && this.css(_opts.style);
//加载默认数据，向第一个选择框填充数据
this.load(_opts.defaultLoadSelectIndex, _opts.defaultParentId);
_opts.texts.length > 0 && this.selected(_opts.texts);
//给每个选择框绑定change事件
this.$applyTo.each(function (i) {
i < _that.size() - 1 && $(this).bind("change.ld", { target: _that, index: i }, _that.onchange);
})
}
return this;
},
texts: function (ts) {
var that = this;
var $select = this.$applyTo;
var _arr = [];
var txt = null;
var $options;
$select.each(function () {
txt = $(this).children('.' + that.OPTIONS_CLASS + ':selected').text();
_arr.push(txt);
})
return _arr;
},
/**
* 获取联动选择框的数量
* @return {Number} 选择框的数量
*/
size: function () {
return this.$applyTo.size();
},
/**
* 设置选择框的样式
* @param {Object} style 样式
* @return {Object} this
*/
css: function (style) {
style && this.$applyTo.css(style);
return this;
},
/**
* 读取数据，并写入到选择框
* @param {Number} selectIndex 选择框数组的索引值
* @param {String} parent_id  父级id
*/
load: function (selectIndex, parent_id, callback) {
var _that = this;
//清理index以下的选择框的选项
for (var i = selectIndex; i < _that.size(); i++) {
_that.removeOptions(i);
}
//存在缓存数据,直接使用缓存数据生成选择框的子项；不存在，则请求数据
if (_that.cache[parent_id]) {
_that._create(_that.cache[parent_id], selectIndex);
_that.$applyTo.eq(selectIndex).trigger("afterLoad");
if (callback) callback.call(this);
} else {
var _ajaxOptions = this.options.ajaxOptions;
var _d = _ajaxOptions.data;
var _parentIdField = this.options.field['parent_id'];
_d[_parentIdField] = parent_id;
//传递给后台的参数
_ajaxOptions.data = _d;
//ajax获取数据成功后的回调函数
_ajaxOptions.success = function (data) {
//遍历数据，获取html字符串
if (data.success) {    //2011-6-1 修改
var _h = _that._getOptionsHtml(data.data);  //2011-5-31 修改
_that._create(_h, selectIndex);
_that.cache[parent_id] = _h;
_that.$applyTo.eq(selectIndex).trigger("afterLoad.ld");
if (callback) callback.call(this);
}
}
$.ajax(_ajaxOptions);
}
},
/**
* 删除指定index索引值的选择框下的选择项
* @param {Number} index 选择框的索引值
* @return {Object} this
*/
removeOptions: function (index) {
this.$applyTo.eq(index).children("." + this.OPTIONS_CLASS).remove();
return this;
},
selected: function (t, completeCallBack) {
var _that = this;
if (t && typeof t == "object" && t.length > 0) {
var $select = this.$applyTo;
_load(_that.options.defaultLoadSelectIndex, _that.options.defaultParentId);
}
/**
* 递归获取选择框数据
* @param {Number} selectIndex 选择框的索引值
* @param {Number} parent_id   id
*/
function _load(selectIndex, parent_id) {
_that.load(selectIndex, parent_id, function () {
var id = _selected(selectIndex, t[selectIndex]);
selectIndex++;
if (selectIndex > _that.size() - 1) {
if (completeCallBack) completeCallBack.call(this);
return;
}
_load(selectIndex, id);
});}
/**
* 选中包含指定文本的选择项
* @param {Number} index 选择框的索引值
* @param {String} text  文本
* @return {Number} 该选择框的value值
*/
function _selected(index, text) {
var id = 0;
_that.$applyTo.eq(index).children().each(function () {
var reg = new RegExp(text);
if (reg.test($(this).text())) {
$(this).attr("selected", true);
id = $(this).val();
return;
}
})
return id;
}
return this;
},
/**
* 选择框的值改变后触发的事件
* @param {Object} e 事件
*/
onchange: function (e) {
//实例化后的对象引用
var _that = e.data.target;
//选择框的索引值
var index = e.data.index;
//目标选择框
var $target = $(e.target);
var _parentId = $target.val();
var _i = index + 1;
_that.load(_i, _parentId);
},
/**
* 将数据源（json或xml）转成html
* @param {Object} data
* @return {String} html代码字符串
*/
_getOptionsHtml: function (data) {
var _that = this;
var ajaxOptions = this.options.ajaxOptions;
var dataType = ajaxOptions.dataType;
var field = this.options.field;
var _h = "";
_h = _getOptions(data, dataType, field).join(""); ;
/**
* 获取选择框项html代码数组
* @param {Object | Array} data 数据
* @param {String} dataType 数据类型
* @param {Object} field 字段
* @return {Array} aStr
*/
function _getOptions(data, dataType, field) {
var optionClass = _that.OPTIONS_CLASS;
var aStr = [];
var id, name;
if (dataType == "json") {
$.each(data, function (i) {
id = data[field.region_id];
name = data[field.region_name];
var _option = "<option value='" + id + "' class='" + optionClass + "'>" + name + "</option>";
aStr.push(_option);

})
} else if (dataType == "xml") {
$(data).children().children().each(function () {
id = $(this).find(field.region_id).text();
name = $(this).find(field.region_name).text();
var _option = "<option value='" + id + "' class='" + optionClass + "'>" + name + "</option>";
aStr.push(_option);
})
}
return aStr;
}
return _h;
},
/**
* 向选择框添加html
* @param {String} _h html代码
* @param {Number} index 选择框的索引值
*/
_create: function (_h, index) {
var _that = this;
this.removeOptions(index);
this.$applyTo.eq(index).append(_h);
}
}
$.fn.ld.defaults = {
/**选择框对象数组*/
selects: null,
/**ajax配置*/
ajaxOptions: {
url: null,
type: 'get',
data: {},
dataType: 'json',
success: function () { },
beforeSend: function () {}},
/**默认父级id*/
defaultParentId: 0,
/**默认读取数据的选择框*/
defaultLoadSelectIndex: 0,
/**默认选择框中的选中项*/
texts: [],
/**选择框的样式*/
style: null,
/**选择框值改变时的回调函数*/
change: function () { },
field: {
region_id: "CategoryId",
region_name: "CategoryName",
parent_id: "CategoryParentID"
}

}
})(jQuery);