HTML客户端:originalValue =未定义 [英] HTML Client: originalValue = undefined

问题描述

我想在客户端JavaScript更改监听器中比较新旧值.每次我检查contentItem.originalValue时，它都是未定义的.该属性在那里，只是未设置.有什么想法吗?

I want to compare old and new values in a client-side JavaScript change listener.  Every time I check contentItem.originalValue it is undefined.  The property is there it's just not set.  Any ideas?

这是SL客户端的方法:

This is the way for SL client:

TIA，

乔什

推荐答案

我也没有看到使用过originalValue.在dataBind函数中，contentItem在范围外，但作为 此仍保留对其原始数据的引用.

I haven't seen originalValue used either. In the dataBind function contentItem is out-of-scope but is passed as this which still keeps a reference to its original data.

以屏幕属性名字"为例:

As an example for a screen property Firstname:

myapp.AddEditEngineer.Firstname_postRender = function (element, contentItem) {
    // Write code here.
    contentItem.dataBind('value', function (newValue) {
        if (this.bindingSource.data.Firstname === this.value)
            console.log('No changes');
        else {
            console.log(newValue);
        }
    });
};

...将区分新值和原始值.

...will distinguish between a new and original values.

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