ExtJS 4 - please explain Model & Store

Question

I am trying to get my head round what appears to be the simplest of things:

I want to load a collection of objects via a JSON-returning server-side call,

why do all these return something unexpected?

> modelStore.data.items[0].Id
undefined
> modelStore.data.items[0].getId()
undefined
> modelStore.data.items[0].getTitle()
TypeError: Object [object Object] has no method 'getTitle'
> modelStore.getById(1)
null
> modelStore.getTotalCount()
1
> modelStore.first()
Ext.Class.newClass < should be PegModel??

The code:

Ext.define('PegfileApp.model.PegModel', {

  extend: 'Ext.data.Model',

  fields: ['Id', 'Title'],

  //hasMany: {model: 'RootDimension', name: 'rootDimensions'},

  proxy:
  {
    type: 'ajax',
    url: 'PegModel',
    timeout: 120000,
    noCache: false,
    reader:
    {
      root: 'PegModel',
      successProperty: 'success'
    }
  }
});

Ext.define('PegfileApp.store.PegModels', {
  extend: 'Ext.data.Store',
  model: 'PegfileApp.model.PegModel',
  autoLoad: true,
  autoSync: false,
  proxy: {
    type: 'ajax',
    url: 'PegModel',
    reader: {
      type: 'json',
      root: 'PegModels',
      successProperty: 'success'
    }
  }
});

The data:

{"PegModels":[{"Title":"PegModel","Id":1}],"success":true}

I understood for each property defined on the Model, we have a corresponding getter: get{PropertyName}()?

Do i need to cast the "Record" somehow to a "Model"?

sha sha · Accepted Answer · 2012-07-11T12:51:13

You're almost there. :)

Store has array of models but you don't access them directly via items[]. You use store.getAt(index) method instead if store.items[index] for example.

Also check out store.find() method and similar to it to get an idea how to get that index for particular record.

Once you got record which will be model instance you use record.get('fieldname') to get different fields.

ExtJS 4 - please explain Model & Store

2 Answers