Added fields to Model dynamically in touch2

[FanOfExt]

Hi,
I've searched this form and online extensively looking for a way to add fields to my model dynamically. I found many posts on the topic but no concrete working solution.

This is my model, I only know one field upfront, the rest I have to set based on a configuration that I retrieve.

Ext.define('CVM.model.ListDetailMod', {
    extend: 'Ext.data.Model',
    config:{
        fields:['ItemId'],
        idProperty:'ItemId'
    }
});

No I cannot define all the fields upfront, it must be dynamic. By the way I got this working in an extjs 4 app so I'm confused as to why it isnt working with touch2.

I found one post recommending this approach:

var myModel = Ext.ModelManager.getModel('CVM.model.ListDetailMod');
myModel.prototype.fields.add(new Ext.data.Field("Id"));

However it did not work for me!


Why cant I just do something like this? (which does not work by the way, but I found a slight variation worked for my grid model in extjs4).

var fieldsArray = new Array();
fieldsArray[0]="ItemId";
fieldsArray[1]="Id";

var model = Ext.ModelManager.getModel('CVM.model.ListDetailMod');
model.setFields(fieldsArray);

In both scenarios I know they dont work because the records are not populated by my store. However if I hard code the one "ItemId" field on my model and try to set the rest dynamically I do see data for "ItemId" but not for any of the other ones. If I set all fields on my model dynamically including "ItemId" then my store records dont have any data i.e. when I do store.getAt(0).get("ItemId") I get "undefined".


Thanks for the help.

[bluehipy]

You want to add fields to a class or to an instance model?

[FanOfExt]

Hi,
Sorry I'm rather new to ext and touch so I'm not sure what exactly either of those are.

Basically I define a model without fields in a js file. I also have a store with reader and proxy in another js file.

At runtime I want to add fields to the model used by my store because I retrieve a set of records into my store with fields that I only know at runtime.

Now that I think about it, I think I'm trying to add fields to an instance model. Class would mean in the Js file. Is that correct?

Thank you

[bluehipy]

Ext.define will create a "class" definition, Ext.create will create an instance.

I think you can create the definition of the model also at run time, and with some tweaking of a custom reader/prtoxy/store you can create the model as you need it.


Some inspiration:


Ext.define('User', {
extend: 'Ext.data.Model',
config:{
fields: ['name','age','phone']
},
addField:function(field){
var fields = this.getFields().items || [];
var data = this.getData(); // preserve data
fields.push(field);
this.setFields( fields );
this.setData( data );
}
});




var user = Ext.create('User',{name:'blue', age:35, phone:'0723538xxx' } );


user.addField({name:'caffee', type:'string'});


user.set('caffee','Arabica');


console.log( user.get('caffee') );


console.log(user.getData() );

[stewardsencha]

So it seems there are two approaches.

Build the definition then instatiate it.

or

Add field to an instance (getFields/setFields).

So I wonder...


All other things being equal, which gives the best performance?

All other things being equal, are there any strong reasons to prefer one over the other?