blocks|key|1948440|text|我自己也在看教程，但我认为你必须设置一个属性并使用ko.computed来赋予它的值(来自教程)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948441|function+AppViewModel()+{
this.firstName+=+ko.observable("Bert");
this.lastName+=+ko.observable("Bertington");
this.fullName+=+ko.computed(function(){+
++return+this.firstName()+%2B+"+"+%2B+this.lastName();+
++},this);
}|code-block|syntax|javascript|1948442|然后你可以拥有：|1948443|Full+name:+<strong+data-bind="text:+fullName">|1948444|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Well I am just going through the tutorial myself but I thought you had to set up a property and use ko.computed to give it its value (from the tutorial):

<pre><code>function AppViewModel() {
this.firstName = ko.observable("Bert");
this.lastName = ko.observable("Bertington");
this.fullName = ko.computed(function(){ 
 return this.firstName() + " " + this.lastName(); 
 },this);
}
</code></pre>

Then you can have:

<pre><code>Full name: &lt;strong data-bind="text: fullName"&gt;&lt;/strong&gt;
</code></pre>

blocks|key|1735031|text|您可以使用任意的JavaScript表达式进行绑定，但请记住，它们是在视图模型的上下文中计算的，因此表达式中的所有函数都必须是视图模型的属性。在您的示例中，MySomeFunction必须是视图模型的属性。如果您使用映射插件创建视图模型，则可以将其他函数附加到视图模型，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1735032|var+viewModel+=+ko.mapping.fromJS(data.d)
viewModel.MySomeFunction+=+function(...){...};|code-block|syntax|javascript|1735033|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use arbitrary JavaScript expressions for bindings, but keep in mind that they are evaluated in the viewmodel's context, so all functions in the expression have to be properties of viewmodel. In your case, MySomeFunction has to be a property of your viewmodel. If you create your viewmodel using mapping plugin, you can attach additional functions to the viewmodel like this:

<pre><code>var viewModel = ko.mapping.fromJS(data.d)
viewModel.MySomeFunction = function(...){...};
</code></pre>

blocks|key|1948520|text|我在尝试计算表格单元格条目时遇到了类似的问题。对我来说起作用的是在我的数据模型中包含'MySomeFunction‘，然后将我的表单元格数据绑定为：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948521|<td+data-bind="text:+$root.MySomeFunction(SomeProperty)"></td>|code-block|syntax|javascript|1948522|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I had a similar problem trying to calculate table cell entries. What worked for me was including 'MySomeFunction' in my data model, and then data-binding my table cells as:

<pre><code>&lt;td data-bind="text: $root.MySomeFunction(SomeProperty)"&gt;&lt;/td&gt;
</code></pre>

blocks|key|1948532|text|我已经通过使用上下文成功地做到了这一点。如果你需要完整的代码，我可以发给你。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948533|<h2+class="text"+data-bind="html:+currentProgram($context)"></h2>

function+currentProgram(context){
++var+title+=+'<font+size="1">'+%2B+context.$data.name+%2B+'';
++return+title;
}|code-block|syntax|javascript|1948534|您还需要设置此|1948535|+++++++$.ajaxSetup({
++++++++++async:+false
++++++++});|1948536|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I have managed to do this by using the context. If you need the whole code I can send it to you.

<pre><code>&lt;h2 class="text" data-bind="html: currentProgram($context)"&gt;&lt;/h2&gt;

function currentProgram(context){
 var title = '&lt;font size="1"&gt;' + context.$data.name + '&lt;/font&gt;';
 return title;
}
</code></pre>

You will also need to set this

<pre><code> $.ajaxSetup({
 async: false
 });
</code></pre>

blocks|key|1735057|text|<div+style="font-size:18px;float:left;width:95%25"+data-bind="html:+trimString(AccountName,25)"></div>

function+trimString(value,+maxLen)+{

++++//Return+undefined,+and+short+strings
++++if+(value+===+undefined)+return+undefined;
++++if+(value.length+<+maxLen)+return+value;

++++return+value.substring(0,+(maxLen+-+1));++++
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1735058|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&lt;div style="font-size:18px;float:left;width:95%" data-bind="html: trimString(AccountName,25)"&gt;&lt;/div&gt;

function trimString(value, maxLen) {

 //Return undefined, and short strings
 if (value === undefined) return undefined;
 if (value.length &lt; maxLen) return value;

 return value.substring(0, (maxLen - 1)); 
}
</code></pre>

Is there a way i can call JavaScript function on data-bind like this:

<pre><code>&lt;span id="lblSomePropVal" data-bind="text: MySomeFunction(SomeProperty())" &gt;&lt;/span&gt;
</code></pre>

What i am trying to do is call MySomeFunction with the value of SomeProperty of my viewmodel. My SomeFunction will return some text based on value passed and that will be displayed in the span lblSomePropVal.

I tried it the way i have written in the example but it throws binding error.

Am i missing something here or is there any other way of doing this?

This is the error i am getting:

<pre><code>Microsoft JScript runtime error: Unable to parse bindings.
Message: [object Error];
Bindings value: text: MySomeFunction(SomeProperty())
</code></pre>

Knockout.js - javascript function on data-bind

有没有一种方法可以像这样在数据绑定上调用JavaScript函数：我尝试做的是用我的视图模型的SomeProperty值调用MySomeFunction。...

问Knockout.js -数据绑定上的javascript函数
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