1.当前要准备好js,下面的代码在网上下的,作者不可考,向这位IT工作者致敬! linkage.js (仅在changeLinkage方法中加入一个SetAssociatedDropDownListValue(element);) 此js库依赖于prototype.js而运行,网上到处有下的
var Linkage = Class.create();
Linkage.prototype = {
initialize : function(dataSrc, xmlFile) {
this.dataSrc = dataSrc;
this.xmlFile = xmlFile;
},
dataSrc : "" ,
xmlFile : "" ,
BLANK_SELECT : "-----Select-----" ,
AllMenuArr : new Array() ,
MenuIdArr : new Array() ,
MenuInfoArr : new Array() ,
iDepth : -1 ,
tree : function(dataSrc, Element) {
var node = "";
if(Element.nodeType != 3) {
node = Element;
this.onElement(dataSrc, Element);
}
if(Element.hasChildNodes) {
for(var i=0;i if (Element.childNodes[i].nodeType != 3) {
this.iDepth++;
this.tree(dataSrc, Element.childNodes[i]);
}
}
}
if(node) {
this.endElement();
}
} ,
onElement : function(dataSrc, ele) {
if (V(ele, "Value") != null) {
if (this.MenuInfoArr[dataSrc] == null) {
this.MenuInfoArr[dataSrc] = new Array();
}
if (this.MenuInfoArr[dataSrc][this.iDepth] == null) {
this.MenuInfoArr[dataSrc][this.iDepth] = new Array();
}
this.MenuInfoArr[dataSrc][this.iDepth].push(new MenuInfo(V(ele.parentNode, "Value") , V(ele, "Value") , (V(ele, "Desc")==null ? V(ele, "Value") : V(ele, "Desc"))));
}
} ,
endElement : function() {
this.iDepth--;
} ,
initBlank : function(element) {
element.length = 0;
element.options.add(new Option( this.BLANK_SELECT, "" ));
element.selectedIndex = 0;
} ,
updateAllLast : function(dataSrc, nLevel) {
for(i = nLevel+1; i < this.MenuIdArr[dataSrc].length; i++) {
childNode = (this.MenuIdArr[dataSrc][i]);
this.initBlank(childNode);
childNode.disabled = true;
}
} ,
initLinkage : function(dataSrc, sValue, nLevel) {
nLevel = Number(nLevel);
if (nLevel > this.MenuIdArr[dataSrc].length || nLevel < 1) {
return;
}
currNode = (this.MenuIdArr[dataSrc][nLevel-1]);
childNode = (this.MenuIdArr[dataSrc][nLevel]);
if (currNode.disabled) {
return;
}
for (i=0; i if (currNode.options[i].value == sValue) {
currNode.selectedIndex = i;
break;
}
}
if (childNode != null) {
currArr = this.AllMenuArr[dataSrc][nLevel];
this.initBlank(childNode);
for(i=0; i if (currArr[i].parentValue == sValue) {
childNode.options.add(new Option(currArr[i].Desc, currArr[i].Value));
}
}
if ((sValue != '') && (childNode.length > 1)) {
childNode.disabled = false;
} else {
childNode.disabled = true;
}
}
this.updateAllLast(dataSrc, nLevel);
} ,
changeLinkage : function(element) {
SetAssociatedDropDownListValue(element);
this.initLinkage(V(element , "USEDATA"), F(element), V(element , "SUBCLASS"));
} ,
setDataSrc : function(dataSrc) {
this.dataSrc = dataSrc;
} ,
setXmlFile : function(xmlFile) {
this.xmlFile = xmlFile;
} ,
init : function() {
var rootEle = loadXML(this.dataSrc, this.xmlFile);
this.tree(this.dataSrc, rootEle);
this.iDepth = -1;
for (i=0; i if (this.AllMenuArr[this.dataSrc] == null) {
this.AllMenuArr[this.dataSrc] = new Array();
}
this.AllMenuArr[this.dataSrc].push(this.MenuInfoArr[this.dataSrc][i]);
}
var selectNodes = document.getElementsByTagName("select");
for (i=0; i if (V(selectNodes[i] , "USEDATA") == this.dataSrc) {
if (this.MenuIdArr[this.dataSrc] == null) {
this.MenuIdArr[this.dataSrc] = new Array();
}
var subClass = Number(V(selectNodes[i] , "SUBCLASS")) - 1;
this.MenuIdArr[this.dataSrc][subClass] = V(selectNodes[i] , "id");
Event.observe(selectNodes[i], "change", this.changeLinkage.bind(this, selectNodes[i]));
}
}
firstNode = (this.MenuIdArr[this.dataSrc].first());
this.initBlank(firstNode);
for (i=0; i firstNode.options.add(new Option(this.AllMenuArr[this.dataSrc].first()[i].Desc, this.AllMenuArr[this.dataSrc].first()[i].Value));
}
this.updateAllLast(this.dataSrc, 0);
}
}
var MenuInfo = Class.create();
MenuInfo.prototype = {
initialize : function(sParentValue, sValue, sDesc) {
this.parentValue = sParentValue;
this.Value = sValue;
this.Desc = sDesc;
}
}
function V(ele, attr) {
return ele.getAttribute(attr);
}
function createXMLDom() {
if (window.ActiveXObject)
var xmldoc = new ActiveXObject("Microsoft.XMLDOM");
else
if (document.implementation&&document.implementation.createDocument)
var xmldoc = document.implementation.createDocument("","doc",null);
xmldoc.async = false;
xmldoc.preserveWhiteSpace=true;
return xmldoc;
}
function loadXML(dataSrc, xmlFile) {
if (xmlFile == null) {
if (window.ActiveXObject) {
return (dataSrc).documentElement;
} else {
for (i=0; i<(dataSrc).childNodes.length; i++) {
if ((dataSrc).childNodes[i].tagName != null) {
return (dataSrc).childNodes[i];
break;
}
}
}
} else {
var xmlDom = createXMLDom();
try{
xmlDom.load(xmlFile);
}catch(e){
alert("lost xml File");
}
return xmlDom.documentElement;
}
}
2.简单的控件类 必须的属性有USEDATA和Xml,USEDATA可以随便指定,应该是为了页面上有多个联动而设计的,现在没有支持,另一个xml属性用于指定xml格式数据源 ,另外依赖于外部js /Script/linkage.js和/Script/prototype.js
.using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Web.UI.WebControls;
using System.Web.UI;
using System.ComponentModel;
using System.Collections.Specialized;
namespace Blackant.Controls
{
[DefaultProperty("Value")]
public class AssociatedDropDownList : WebControl, IPostBackDataHandler
{
字段#region 字段
private string _Xml="";
private XmlDocument _XmlDoc;
#endregion
属性#region 属性
[Bindable(true)]
[Category("Appearance")]
[DefaultValue("0")]
[Localizable(true)]
public string Value
{
get
{
return ViewState["Value"] == null ? "0" : ViewState["Value"].ToString();
}
set
{
ViewState["Value"] = value;
}
}
public string USEDATA
{
get
{
if (ViewState["USEDATA"] != null)
return ViewState["USEDATA"].ToString();
return String.Empty;
}
set { ViewState["USEDATA"] = value; }
}
/**////
/// 字符串形式表达的xml格式文档
///
public string Xml {
get { return _Xml; }
set { _Xml = value;
}
}
#endregion
私有方法#region 私有方法
int GetMaxLevel(XmlNode parent, int CurLevel)
{
int MaxLevel = CurLevel;
foreach (XmlNode xn in parent.ChildNodes)
{
if (xn.NodeType == XmlNodeType.Element)
{
int tmpLevel = GetMaxLevel(xn, CurLevel + 1);
MaxLevel = MaxLevel > tmpLevel ? MaxLevel : tmpLevel;
}
}
return MaxLevel;
}
#endregion
重载事件#region 重载事件
protected override void CreateChildControls()
{
_XmlDoc = new XmlDocument();
_XmlDoc.LoadXml(_Xml);
XmlElement root = _XmlDoc.DocumentElement;
int maxLevel = GetMaxLevel(root, 1);
for (int i = 1; i < maxLevel; i++)
{
DropDownList ddl = new DropDownList();
ddl.Attributes.Add("USEDATA", USEDATA);
ddl.Attributes.Add("SUBCLASS", i.ToString());
ddl.ID = ddl.ClientID;
Controls.Add(ddl);
}
base.CreateChildControls();
}
protected override void OnPreRender(EventArgs e)
{
Page.RegisterRequiresPostBack(this);
Page.ClientScript.RegisterHiddenField(this.ClientID, Value);
base.OnPreRender(e);
}
protected override void Render(HtmlTextWriter writer)
{
StringBuilder sb = new StringBuilder();
sb.AppendFormat("", USEDATA);
sb.Append(_Xml);
sb.Append("");
sb.Append(" ");
sb.Append(" ");
sb.Append("");
Page.ClientScript.RegisterStartupScript(typeof(string), USEDATA, sb.ToString());
base.Render(writer);
}
#endregion
IPostBackDataHandler Members#region IPostBackDataHandler Members
//private static readonly object EventTextChanged = new object();
public virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection)
{
//比较初始数据presentValue和回传数据postedValue
string postedValue = postCollection[postDataKey];
string presentValue = Value;
if (presentValue == null || postedValue != presentValue)
{
Value = postedValue;
return true;
}
return false;
}
void IPostBackDataHandler.RaisePostDataChangedEvent()
{
}
#endregion
}
}
3简单运用,
<%@ Page Language="C#" %>
<%@ Register Assembly="Blackant.Controls" Namespace="Blackant.Controls" TagPrefix="bawc" %>
Untitled Page
来源:CSDN
