How to add dynamically store data to combobox

Am going to bind the data to combobox store dynamically. below is the combobox how to define the properties and all.

xtype: 'combobox',

width: '10%',

reference: 'Amount',

fieldLabel: 'Amount',

labelSeparator: "",

labelAlign: 'top',

queryMode: 'local',

store: new Ext.data.JsonStore({

fields: ['id', 'display', 'value']

}),

displayField: 'display',

valueField: 'value',

emptyText: 'Select',

name: 'relationType',

submitEmptyText: false,

allowBlank: false,

style: '141px',

listeners: {

change: 'onSelectionChange'

}

In controllerthe code will be.

var multiplyCombo = fieldsContainer.down('combobox').getStore();

var bulkAddArray = [];

for (var i = 1; i <= multiplyFactor; i++) {

bulkAddArray.push({

display: i,

value: i

});

}

multiplyCombo.loadData(bulkAddArray, true);