ASP.Net 2.0 的 TreeVIEw 控件功能雖說強大,但其客戶端控制很遜色,本文將講解 TreeVIEw 的客戶端實現原理,並實現兩個個性化操作:
(1) 節點的全部打開和關閉;
TreeNode Expand(or Collapse) all
(2) 只打開一個節點(關閉其他兄弟節點)。
just one node expanded(when a clIEnt expand one node all other will collaps)
用記事本打開頁面源代碼,可以找到一下兩個腳本引用:
<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,並以 .JS 命名,另一個同樣操作。分析第二個腳本文件,可以看到TreeView的很多客戶端函數,其中關鍵的一個 TreeVIEw_ToggleNode 就是客戶端點擊時觸發的事件。
要想做個性化的操作,就得從 TreeVIEw_ToggleNode 事件下手。我們無法更改.Net封裝好的腳本,只有“重寫”。所謂的重寫就是在原來的函數之後添加一個同名函數(因為JS對於同名函數只調用最後一個)。
TreeVIEw_ToggleNode 的原函數:
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. 節點的全部打開和關閉:
<html XMLns="http://www.w3.org/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. 只打開一個節點(關閉其他兄弟節點)
<html XMLns="http://www.w3.org/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. 只打開一個節點(關閉其他兄弟節點)------------------------------------------
function TreeVIEw_ToggleNode(data, index, node, lineType, children)
{
var img = node.childNodes[0];
var newExpandState;
try {
//***折疊兄弟節點------------------------
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);
}
//折疊兄弟節點
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>