剛開始接觸menu控件，感覺怎么這么別扭啊。

首先說數據訪問部分，為了所謂的provider pattern，一層一層的包裝，而且都是些黑盒子，雖然概念是挺先進，結構好象也很清楚，但還是讓我覺的迷迷糊糊，至于嘛，只是想做幾個數據驅動的menu而已。還有那個前臺的menu類，那么多的properties，尤其想到menu類也是個黑盒子，一點都不知道，它生成的xhtml會是什么樣的，而我只有一點點css知識而已，想到這里連嘗試的欲望都沒了。還不如自己動手親自寫一個menu呢，網上好象有好多現成的javascript類，比如這個：

div_css 結構的，雖然沒有asp.net 控件那么漂亮，可也很是實用，至少都是透明的。不過后臺有點麻煩，當時的想法是：

1 設計一個類sitemap，從數據庫里讀導航信息，然后存到一個dataset中，

2 在application_start 事件處理函數中 實例化一個sitemap 和一個sqlcachedependency ，插入到cache中。

3 一個dependency的回調函數,以更新cache中的數據

4 從cache中提取數據生成menu。

這樣一來可以想象default.master的代碼的代碼會亂七八糟。非但不太容易寫，寫好的代碼也不太容易復用。而且還有關于cache的很多問題。

肯定有其他辦法，asp.net好多東西我都沒有接觸過。不過現在想想 provider pattern還是不錯，一層api連接表示層，一層api連接數據訪問層。

被迫學習menu類，希望它不要太讓人意外。終于明白為什么開源讓那么多人激動，開放透明啊！

/**//*****************************************************
* ypslideoutmenu
* 3/04/2001
*
* a nice little script to create exclusive, slide-out
* menus for ns4, ns6, mozilla, opera, ie4, ie5 on
* mac and win32. i've got no linux or unix to test on but
* it should(?) work...
*
* revised:
* - 08/29/2002 : added .hideall()
* - 04/15/2004 : added .writecss() to support more
*
   
       
           
                than 30 menus.
*
* --youngpup--
*****************************************************/
ypslideoutmenu.registry = []
ypslideoutmenu.anilen = 250
ypslideoutmenu.hidedelay = 1000
ypslideoutmenu.mincpuresolution = 10
// constructor
function ypslideoutmenu(id, dir, left, top, width, height)
...{
this.ie = document.all ? 1 : 0
this.ns4 = document.layers ? 1 : 0
this.dom = document.getelementbyid ? 1 : 0
if (this.ie || this.ns4 || this.dom) ...{
this.id = id
this.dir = dir
this.orientation = dir == "left" || dir == "right" ? "h" : "v"
this.dirtype = dir == "right" || dir == "down" ? "-" : "+"
this.dim = this.orientation == "h" ? width : height
this.hidetimer = false
this.anitimer = false
this.open = false
this.over = false
this.starttime = 0
this.gref = "ypslideoutmenu_"+id
eval(this.gref+"=this")
ypslideoutmenu.registry[id] = this
var d = document
var strcss = "";
strcss += '#' + this.id + 'container { visibility:hidden; '
strcss += 'left:' + left + 'px; '
strcss += 'top:' + top + 'px; '
strcss += 'overflow:hidden; z-index:10000; }'
strcss += '#' + this.id + 'container, #' + this.id + 'content { position:absolute; '
strcss += 'width:' + width + 'px; '
strcss += 'height:' + height + 'px; '
strcss += 'clip:rect(0 ' + width + ' ' + height + ' 0); '
strcss += '}'
this.css = strcss;
this.load()
}
}
ypslideoutmenu.writecss = function() ...{
document.writeln('<style type="text/css">');
for (var id in ypslideoutmenu.registry) ...{
document.writeln(ypslideoutmenu.registry[id].css);
}
document.writeln('</style>');
}
ypslideoutmenu.prototype.load = function() ...{
var d = document
var lyrid1 = this.id + "container"
var lyrid2 = this.id + "content"
var obj1 = this.dom ? d.getelementbyid(lyrid1) : this.ie ? d.all[lyrid1] : d.layers[lyrid1]
if (obj1) var obj2 = this.ns4 ? obj1.layers[lyrid2] : this.ie ? d.all[lyrid2] : d.getelementbyid(lyrid2)
var temp
if (!obj1 || !obj2) window.settimeout(this.gref + ".load()", 100)
else ...{
this.container = obj1
this.menu = obj2
this.style = this.ns4 ? this.menu : this.menu.style
this.homepos = eval("0" + this.dirtype + this.dim)
this.outpos = 0
this.accelconst = (this.outpos - this.homepos) / ypslideoutmenu.anilen / ypslideoutmenu.anilen
// set event handlers.
if (this.ns4) this.menu.captureevents(event.mouseover | event.mouseout);
this.menu.onmouseover = new function("ypslideoutmenu.showmenu('" + this.id + "')")
this.menu.onmouseout = new function("ypslideoutmenu.hidemenu('" + this.id + "')")
//set initial state
this.endslide()
}
}
ypslideoutmenu.showmenu = function(id)
...{
var reg = ypslideoutmenu.registry
var obj = ypslideoutmenu.registry[id]
if (obj.container) ...{
obj.over = true
for (menu in reg) if (id != menu) ypslideoutmenu.hide(menu)
if (obj.hidetimer) ...{ reg[id].hidetimer = window.cleartimeout(reg[id].hidetimer) }
if (!obj.open && !obj.anitimer) reg[id].startslide(true)
}
}
ypslideoutmenu.hidemenu = function(id)
...{
var obj = ypslideoutmenu.registry[id]
if (obj.container) ...{
if (obj.hidetimer) window.cleartimeout(obj.hidetimer)
obj.hidetimer = window.settimeout("ypslideoutmenu.hide('" + id + "')", ypslideoutmenu.hidedelay);
}
}
ypslideoutmenu.hideall = function()
...{
var reg = ypslideoutmenu.registry
for (menu in reg) ...{
ypslideoutmenu.hide(menu);
if (menu.hidetimer) window.cleartimeout(menu.hidetimer);
}
}
ypslideoutmenu.hide = function(id)
...{
var obj = ypslideoutmenu.registry[id]
obj.over = false
if (obj.hidetimer) window.cleartimeout(obj.hidetimer)
obj.hidetimer = 0
if (obj.open && !obj.anitimer) obj.startslide(false)
}
ypslideoutmenu.prototype.startslide = function(open) ...{
this[open ? "onactivate" : "ondeactivate"]()
this.open = open
if (open) this.setvisibility(true)
this.starttime = (new date()).gettime()
this.anitimer = window.setinterval(this.gref + ".slide()", ypslideoutmenu.mincpuresolution)
}
ypslideoutmenu.prototype.slide = function() ...{
var elapsed = (new date()).gettime() - this.starttime
if (elapsed > ypslideoutmenu.anilen) this.endslide()
else ...{
var d = math.round(math.pow(ypslideoutmenu.anilen-elapsed, 2) * this.accelconst)
if (this.open && this.dirtype == "-") d = -d
else if (this.open && this.dirtype == "+") d = -d
else if (!this.open && this.dirtype == "-") d = -this.dim + d
else d = this.dim + d
this.moveto(d)
}
}
ypslideoutmenu.prototype.endslide = function() ...{
this.anitimer = window.cleartimeout(this.anitimer)
this.moveto(this.open ? this.outpos : this.homepos)
if (!this.open) this.setvisibility(false)
if ((this.open && !this.over) || (!this.open && this.over)) ...{
this.startslide(this.over)
}
}
ypslideoutmenu.prototype.setvisibility = function(bshow) ...{
var s = this.ns4 ? this.container : this.container.style
s.visibility = bshow ? "visible" : "hidden"
}
ypslideoutmenu.prototype.moveto = function(p) ...{
this.style[this.orientation == "h" ? "left" : "top"] = this.ns4 ? p : p + "px"
}
ypslideoutmenu.prototype.getpos = function(c) ...{
return parseint(this.style[c])
}
ypslideoutmenu.prototype.onactivate = function() ...{ }
ypslideoutmenu.prototype.ondeactivate = function() ...{ }