ExtJS 4实例化模型的id设置为0 [英] ExtJS 4 instantiated model has id set to 0

问题描述

如果我定义这样的实体:

If I define an entity like this:

Ext.define('MyApp.model.Entity', {
    extend : 'Ext.data.Model',
    fields : [ {
        name : 'id',
        type : 'int'
    } ]
});

然后实例化它并使用以下命令输出其ID:

And then instantiate it and output its id with:

var entity = Ext.create('MyApp.model.Entity');
console.log(entity.getId());

我得到的输出是0.我希望它是undefined.为什么会这样?

I'm getting 0 for the output. I would expect it to be undefined. Why is that?

推荐答案

有两个可能的原因.

首先，因为您在字段中使用名称id. Ext.data.Model具有idProperty配置，默认为id，用于定义要与其他字段区别对待的字段名称. getId方法等同于get(idProperty).

First, because you're using the name id for a field. Ext.data.Model has the idProperty config which defaults to id, defining the name of the field to be treated differently than the rest. The getId method is the equivalent of get(idProperty).

第二，因为id的类型是int，在这种情况下，该字段的默认值为0(除非您使用useNull字段配置).

Second, because the type of id is int, in which case the default value for the field is 0 (unless you use the useNull field config).

我个人试图避免将id用于模型属性，因为它倾向于与几乎所有内容发生冲突.使用recordId之类的东西，我从来没有遇到问题.

I personally try to avoid using id for a model property because of its tendency to collide with pretty much everything. I've never had problems using something like recordId or something similar.

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