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asp.net 2.0 的 TreeView 控件功能雖說(shuō)強(qiáng)大,但其客戶端控制很遜色,本文將講解 TreeView 的客戶端實(shí)現(xiàn)原理,并實(shí)現(xiàn)兩個(gè)個(gè)性化操作：
(1) 節(jié)點(diǎn)的全部打開和關(guān)閉；
Client Side Expand/Collapse All Nodes For ASP.NET 2.0 TreeView.
(2) 只打開一個(gè)節(jié)點(diǎn)(關(guān)閉其他兄弟節(jié)點(diǎn))。
Just one expanded node in ASP.NET 2.0 TreeView (When a client expand one node all other will collaps)
用記事本打開頁(yè)面源代碼，可以找到一下兩個(gè)腳本引用：
<script src="/WebUI/WebResource.axd?d=RAQeBcDUNuP9iuS8q3tNEw2&t=633300220640000000" type="text/javascript"></script>
<script src="/WebUI/WebResource.axd?d=JuTdJhq3NM8Jq_RhssAkEg2&t=633300220640000000" type="text/javascript"></script>
將"/WebUI/WebResource.axd?d=RAQeBcDUNuP9iuS8q3tNEw2&t=633300220640000000"拷到地址欄尾，下載腳本，并以 .js 命名，另一個(gè)同樣操作。分析第二個(gè)腳本文件，可以看到TreeView的很多客戶端函數(shù)，其中關(guān)鍵的一個(gè) TreeView_ToggleNode 就是客戶端點(diǎn)擊時(shí)觸發(fā)的事件。
要想做個(gè)性化的操作，就得從 TreeView_ToggleNode 事件下手。我們無(wú)法更改.net封裝好的腳本，只有“重寫”。所謂的重寫就是在原來(lái)的函數(shù)之后添加一個(gè)同名函數(shù)（因?yàn)閖s對(duì)于同名函數(shù)只調(diào)用最后一個(gè)）。
TreeView_ToggleNode 的原函數(shù)：
function TreeView_ToggleNode(data, index, node, lineType, children) {
var img = node.childNodes[0];
var newExpandState;
try {
if (children.style.display == "none") {
children.style.display = "block";
newExpandState = "e";
if ((typeof(img) != "undefined") && (img != null)) {
if (lineType == "l") {
img.src = data.images[15];
}
else if (lineType == "t") {
img.src = data.images[12];
}
else if (lineType == "-") {
img.src = data.images[18];
}
else {
img.src = data.images[5];
}
img.alt = data.collapseToolTip.replace(/\{0\}/, TreeView_GetNodeText(node));
}
}
else {
children.style.display = "none";
newExpandState = "c";
if ((typeof(img) != "undefined") && (img != null)) {
if (lineType == "l") {
img.src = data.images[14];
}
else if (lineType == "t") {
img.src = data.images[11];
}
else if (lineType == "-") {
img.src = data.images[17];
}
else {
img.src = data.images[4];
}
img.alt = data.expandToolTip.replace(/\{0\}/, TreeView_GetNodeText(node));
}
}
}
catch(e) {}
data.expandState.value = data.expandState.value.substring(0, index) + newExpandState + data.expandState.value.slice(index + 1);
}
1. 節(jié)點(diǎn)的全部打開和關(guān)閉(Client Side Expand/Collapse All Nodes)
<html xmlns="http://www./1999/xhtml">
<head runat="server">
<title>LeftMenu_Tree</title>
</head>
<body bgcolor="#DDEDFD">
<form id="form1" runat="server">
<a href="javascript:TreeviewExpandCollapseAll('<%=TreeView1.ClientID%>', true)">Expand
All</a> <a href="javascript:TreeviewExpandCollapseAll('<%=TreeView1.ClientID%>', false)">
Collapse All</a>
<asp:TreeView ID="TreeView1" SkinID="tvClass" runat="server" ShowLines="true" NodeWrap="false">
</asp:TreeView>
</form>
</body>
</html>
<script language="javascript">
//-----------------------------------------------------------------------------
function $(s){return document.getElementById(s);}
function isNull(_sVal){return (_sVal == "" || _sVal == null || _sVal == "undefined");}
function TreeviewExpandCollapseAll(treeViewId, expandAll)
{
var displayState = (expandAll == true ? "none" : "block");
var treeView = $(treeViewId);
if(treeView)
{
var treeLinks = treeView.getElementsByTagName("a");
var nodeCount = treeLinks.length;
var flag = true;
for(i=0;i<nodeCount;i++)
{
if(treeLinks[i].firstChild.tagName)
{
if(treeLinks[i].firstChild.tagName.toLowerCase() == "img")
{
var node = treeLinks[i];
var level = parseInt(node.id.substr(node.id.length - 1),10);
var childContainer = GetParentByTagName("table", node).nextSibling;
if(!isNull(childContainer))
{
if(flag)
{
if(childContainer.style.display == displayState)
{
TreeView_ToggleNode(eval(treeViewId +"_Data"),level,node,'r',childContainer);
}
flag = false;
}
else
{
if(childContainer.style.display == displayState)
{
TreeView_ToggleNode(eval(treeViewId +"_Data"),level,node,'l',childContainer);
}
}
}
}
}
}//for loop ends
}
}
function GetParentByTagName(parentTagName, childElementObj)
{
var parent = childElementObj.parentNode;
while(parent.tagName.toLowerCase() != parentTagName.toLowerCase())
{
parent = parent.parentNode;
}
return parent;
}
//-----------------------------------------------------------------------------
</script>
2. 只打開一個(gè)節(jié)點(diǎn),關(guān)閉其他兄弟節(jié)點(diǎn)(Just one expanded node, all other will collaps) <html xmlns="http://www./1999/xhtml">
<head runat="server">
<title>LeftMenu_Tree</title>
</head>
<body bgcolor="#DDEDFD">
<form id="form1" runat="server">
<a href="javascript:TreeviewExpandCollapseAll('<%=TreeView1.ClientID%>', true)">Expand
All</a> , <a href="javascript:TreeviewExpandCollapseAll('<%=TreeView1.ClientID%>', false)">
Collapse All</a>
<asp:TreeView ID="TreeView1" SkinID="tvClass" runat="server" ShowLines="true" NodeWrap="false">
</asp:TreeView>
</form>
</body>
</html>
<script language="javascript">
//2. 只打開一個(gè)節(jié)點(diǎn),關(guān)閉其他兄弟節(jié)點(diǎn)(Just one expanded node, all other will collaps)
function TreeView_ToggleNode(data, index, node, lineType, children)
{
var img = node.childNodes[0];
var newExpandState;
try {
//***折疊兄弟節(jié)點(diǎn)(Collapse Brothers)-----
CollapseBrothers(data,children);
//---------------------------------------
if (children.style.display == "none")
{
children.style.display = "block";
newExpandState = "e";
if ((typeof(img) != "undefined") && (img != null))
{
if (lineType == "l")
{
img.src = data.images[15];
}
else if (lineType == "t")
{
img.src = data.images[12];
}
else if (lineType == "-")
{
img.src = data.images[18];
}
else
{
img.src = data.images[5];
}
img.alt = data.collapseToolTip.replace(/\{0\}/, TreeView_GetNodeText(node));
}
}
else
{
children.style.display = "none";
newExpandState = "c";
if ((typeof(img) != "undefined") && (img != null))
{
if (lineType == "l")
{
img.src = data.images[14];
}
else if (lineType == "t")
{
img.src = data.images[11];
}
else if (lineType == "-")
{
img.src = data.images[17];
}
else
{
img.src = data.images[4];
}
img.alt = data.expandToolTip.replace(/\{0\}/, TreeView_GetNodeText(node));
}
}
}
catch(e) {}
data.expandState.value = data.expandState.value.substring(0, index) + newExpandState + data.expandState.value.slice(index + 1);
}
//折疊兄弟節(jié)點(diǎn)(Collapse Brothers)
function CollapseBrothers(data,childContainer)
{
var parent = childContainer.parentNode;
for(i=0; i< parent.childNodes.length; i++)
{
if(parent.childNodes[i].tagName.toLowerCase() =="div")
{
if(parent.childNodes[i].id != childContainer.id)
{
parent.childNodes[i].style.display = "none"
}
}
else if(parent.childNodes[i].tagName.toLowerCase() =="table")
{
var treeLinks = parent.childNodes[i].getElementsByTagName("a");
if(treeLinks.length > 2)
{
var j=0;
if(treeLinks[j].firstChild.tagName)
{
if(treeLinks[j].firstChild.tagName.toLowerCase() == "img")
{
var img = treeLinks[j].firstChild;
if(i==0)
img.src = data.images[8];
else if(i==parent.childNodes.length-2)
img.src = data.images[14];
else
img.src = data.images[11];
}
}
}
}
}
}
//-----------------------------------------------------------------------------
</script>
注意這句話：所謂的重寫就是在原來(lái)的函數(shù)之后添加一個(gè)同名函數(shù)（因?yàn)閖s對(duì)于同名函數(shù)只調(diào)用最后一個(gè)）。
所以上面的script放在aspx文件的最后引用！
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