Trying to use JSONStore in a combo - extjs

Question

In our application we have a lot of name/value stores, and they are created at load time and put into a JSONStore like so :
Ext.create("Ext.data.JsonStore", {
data: data,
model: 'EM.model.controlUnit.CodeList',
storeId: "cl_" + tableId,
sorters: [{
sorterFn: aSorterFunction
}],
});
The model is pretty simple and looks like this :
Ext.define('EM.model.controlUnit.CodeList', {
extend: 'Ext.data.Model',
fields: [{
name: 'value', type: 'int'
}, {
name: 'label', type: 'string'
}, {
name: 'description', type: 'string'
}]
});
I thought stores were pretty interchangeable so I decided to use the store in the combo (There is no special combo store so I thought a JSONStore must be as good as a SimpleStore). I get the store like so :
var msDataStore = Ext.getStore("cl_t_cl_maritalstatus");
And use the store like so :
{
xtype: 'combo',
fieldLabel: 'Marital Status',
displayField: "label",
valueField: "value",
store: msDataStore
}
The combo is filled with the values from the store when I run the application, however, when I pop down the combo box, this error is thrown :
ext-debug-w-comments.js:9951 Uncaught
Ext.data.proxy.Server.buildUrl(): You are using a ServerProxy but have
not supplied it with a url.
I do not want any server proxy. These are simple locally stored name value collections.
Can JSONStores be used with combos?
If not. What is the best way to convert a JSONStore into something acceptable for the combo. I can chop, change, restructure the store object. But I just want to know if there is something simpler that I can do before going on some kind of long and pointless journey.

Answer 1

This problem is related 'proxy' property. Default proxy for JsonStore is 'ajax';
proxy: {
type : 'ajax',
reader: 'json',
writer: 'json'
}
You should override with 'memory' like that;
proxy: {
type: 'memory'
}
Your final store is;
Ext.create("Ext.data.JsonStore", {
data: data,
model: 'EM.model.controlUnit.CodeList',
storeId: "cl_" + tableId,
proxy: {
type: 'memory'
}
sorters: [{
sorterFn: aSorterFunction
}],
});

Answer 2

A JsonStore without URL is completely acceptable, but you have to make sure the combo does not trigger a load operation when clicking on the dropdown. This is done by adding to the combo definition the config option queryMode:'local':
{
xtype: 'combo',
fieldLabel: 'Marital Status',
displayField: "label",
valueField: "value",
queryMode: 'local',
store: msDataStore
}