extjs 4.1 how can i reset fieldcontainer in a form panel - extjs4.1

Question

I have many fieldcontainer in a form panel. i want to reset only one fieldcontainer rather then whole panel. but i can't do this. how can i do it? here is my code
Ext.define(Fsl.app.getAbsView('V01T007001X04'), {
extend : 'Ext.form.Panel',
alias : Fsl.app.getAlias('V01T007001X04'),
id : 'V01T007001X04'.toLowerCase(),
margin : '0 0 0 0',
initComponent : function(){
this.items =[{
xtype : 'fieldcontainer',
layout : 'vbox',
items :[{
items : [{
xtype : 'fieldcontainer',
layout : 'vbox',
margin : '5 5 0 5',
items : [
{
xtype : 'numberfield',
fieldLabel : 'InvoiceNo',
name : 'invoiceId',
}]
},
{
xtype : 'fieldcontainer',
layout : 'vbox',
margin : '5 0 0 10',
items: [{
xtype : 'datefield',
name : 'date',
fieldLabel : 'Date'
}]
},{
xtype : 'fieldcontainer',
layout : 'vbox',
margin : '5 0 0 10',
items: [{
xtype : 'textfield',
name : 'branchId',
fieldLabel : 'Branch Id',
}]
}]
}]
},{
xtype : 'fieldcontainer',
combineErrors : true,
layout : 'hbox',
items: [{
xtype : 'numberfield',
fieldLabel : 'Article Id',
name : 'articleId',
}]
}];
this.callParent(arguments);
}
});

Answer 1

You should be able to query for the fieldcontainer you want, then run the reset() function on each of the fields inside the container. Start by giving your fieldcontainer an itemId property, so that it can be queried:
{
xtype: 'fieldcontainer',
itemId: 'invoiceCt',
items : [
{
xtype: 'numberfield',
fieldLabel: 'InvoiceNo',
name: 'invoiceId',
}]
},
Then query for the fieldcontainer and reset each field inside:
var fieldContainer = form.down('#invoiceCt');
fieldContainer.items.each(function(f) {
if (Ext.isFunction(f.reset)) {
f.reset();
}
});