專案裡的介面需求: 網站需開放使用者由候選清單挑選多個項目放入組成清單，組成清單的項目要能調整順序。
實作範例如下，就想像從三國武將中挑選精英組團打副本吧!(裡面有個黑大是什麼東西?) 並可調整出場順序。
搬出Knockout，運用下拉選單的options、selectedOptions多選繫結加上JavaScript陣列基本操作，就能讓選取項目在兩個<select>間搬移；至於選取項目在陣列上下移動，以前我只會傻傻用for跑迴圈搬動，學會splice()後，就能用兩行指令優雅地完成。
就這樣，不到90行，搞定收工~ 線上展示
<!DOCTYPEhtml>
<htmlxmlns="http://www.w3.org/1999/xhtml">
<head>
<title>KO範例30 - 可排序的多重選擇器</title>
<style>
select { width: 100px; height: 120px;}</style>
</head>
<body>
<table>
<tr>
<td>
<selectmultipledata-bind="options: candidates, selectedOptions: selCandidates"></select>
</td>
<td>
<inputtype='button'value='>'data-bind="click: pick"/>
<br/>
<inputtype='button'value='<'data-bind="click: unpick"/>
</td>
<td>
<selectmultipledata-bind="options: members, selectedOptions: selMembers"></select>
</td>
<td>
<inputtype='button'value='▲'data-bind="click: moveUp"/>
<br/>
<inputtype='button'value='▼'data-bind="click: moveDown"/>
</td>
</tr>
</table>
<scriptsrc="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.9.1.js"></script>
<script src="http://ajax.aspnetcdn.com/ajax/knockout/knockout-2.2.1.js"></script><script>
function myViewModel() {var self = this;
self.candidates = ko.observableArray(
["關羽", "張飛", "孔明", "呂布", "典韋", "許褚", "黑大"]);
self.selCandidates = ko.observableArray();
self.members = ko.observableArray();
self.selMembers = ko.observableArray();
self.pick = function() { $.each(self.selCandidates(), function(i, m) {self.candidates.remove(m);
self.members.push(m);
});
self.selCandidates([]);
};
self.unpick = function() { $.each(self.selMembers(), function(i, m) {self.members.remove(m);
self.candidates.push(m);
});
self.selMembers([]);
};
function get1stSelMem() {var ary = self.selMembers();if (ary.length) {var mem = ary[0];ary = self.members();
return { array: ary, index: $.inArray(mem, ary), value: mem };}
returnnull;
}
self.moveUp = function() {var res = get1stSelMem();if (res && res.index) {res.array.splice(res.index, 1);
res.array.splice(res.index - 1, 0, res.value);
self.members(res.array);
}
};
self.moveDown = function() {var res = get1stSelMem();if (res && res.index < res.array.length - 1) {res.array.splice(res.index, 1);
res.array.splice(res.index + 1, 0, res.value);
self.members(res.array);
}
};
}
var vm = new myViewModel();
ko.applyBindings(vm);
</script>
</body>
</html>
[KO系列]
http://www.darkthread.net/kolab/labs/default.aspx?m=post