I have a combobox with data from store:
fields: [
    {name: 'name',  type: 'string'},
    {name: 'createDate',  type: 'string'}
]
Field 'createDate' has format "03.05.2015", this combobox outputs only field 'name':
{
    xtype: 'combobox',
    fieldLabel: 'NameText',
    store: 'storeofnames',
    queryMode: 'local',
    displayField: 'name',
    valueField: 'id'
}
I want next:
Combobox output: name + (if date in field createDate >= current date) add in combobox data from 'createDate'.
 
                        
You can do this trick: in your model add item like:
And in your combobox change displayField: