我目前正试图将onchange
的{{1}}事件绑定到一个事件处理程序里面,这是一个对象方法(用TypeScript编写的JavaScript类),如下所示:
HTML:
<select>
&#13;
JS /打字稿:
<div id="readerTemplate" data-win-control="WinJS.Binding.Template">
<div>
<select class="win-dropdown"
data-win-control="WinJS.UI.Repeater"
data-win-options="{data: versions}"
data-win-bind="value: version; onchange: versionChangeHandler">
<option data-win-bind="value: fileName; textContent: versionName">
</option>
</select>
<div class="win-type-title" data-win-bind="textContent: version"></div>
</div>
</div>
&#13;
发生绑定的行:
loadTabsUI(pivot: WinJS.UI.Pivot) {
for (let tab of this.tabs) {
var tabDiv = document.createElement("div");
var pivotItemDiv = document.createElement("div");
var pivotItem = new WinJS.UI.PivotItem(pivotItemDiv);
pivotItemDiv.setAttribute('data-win-bind', 'winControl.header: title');
var rptrDiv = document.createElement("div");
var rptr = new WinJS.UI.Repeater(rptrDiv, { "data": tab.readers, "template": document.getElementById("readerTemplate").winControl });
pivotItem.contentElement.appendChild(rptrDiv);
pivot.items.push(pivotItem);
WinJS.Binding.processAll(pivotItemDiv, tab);
}
}
Reader类与方法:
var rptr = new WinJS.UI.Repeater(rptrDiv, { "data": tab.readers, "template": document.getElementById("readerTemplate").winControl });
&#13;
当class Reader {
...
...
versionChangeHandler(evt: UIEvent): void {
// goal is to execute the following line:
this.setVersionAsync((evt.target as any).value);
}
...
...
}
的选择发生变化时,<select>
会被调用。但是,问题是我无法访问函数内部的正确versionChangeHandler
,这阻止我在正确的对象实例上运行this
,这是使用的对象实例通过setVersionAsync
(在前面的JS绑定中)填充/绑定WinJS.UI.Repeater
。
有关解决此问题的任何想法?
(我在Reader类的构造函数中调用此readerTemplate
,否则我使用绑定命中了异常。)
谢谢!
答案 0 :(得分:1)
然而,问题是我无法在函数内部访问正确的内容。
这是因为背景已经改变。您可以使用以下代码来解决此问题:
class Reader {
public handlerProxy: any;
constructor() {
this.handlerProxy = (evt: UIEvent) => { this.versionChangeHandler(evt, this); }
}
...
...
versionChangeHandler(evt: UIEvent,that): void {
// goal is to execute the following line:
that.setVersionAsync((evt.target as any).value);
}
...
...
}
并在您的HTML中将versionChangeHandler
更改为handlerProxy
:
<div id="readerTemplate" data-win-control="WinJS.Binding.Template">
<div>
<select class="win-dropdown"
data-win-control="WinJS.UI.Repeater"
data-win-options="{data: versions}"
<!--here change versionChangeHandler to handlerProxy.-->
data-win-bind="value: version; onchange: handlerProxy">
<option data-win-bind="value: fileName; textContent: versionName">
</option>
</select>
<div class="win-type-title" data-win-bind="textContent: version"></div>