checkbox and formbind

When using formbind in ext js 3, i can setup my textfields like this:

items:[{
name:'Username',
allowBlank:false
},{
name:'Password',
inputType:'password',
allowBlank:false
}],

but how do i setup a checkbox, which i want to be checked, using formbind, something like allownotchecked: false ?

Something like this?

Code:

---

Ext.ns('Ext.ux.form');

Ext.ux.form.Checkbox = Ext.extend(Ext.form.Checkbox, {
    blankText : 'This field is required',

    getErrors : function() {
        var errors = Ext.ux.form.Checkbox.superclass.getErrors.call(this);

        if (this.allowBlank === false && !this.getValue()) {
            errors.push(this.blankText);
        }

        return errors;
    }
});

Ext.reg('ux-checkbox', Ext.ux.form.Checkbox);

Ext.onReady(function() {

    new Ext.form.FormPanel({
        renderTo    : document.body,
        title        : 'Test',
        monitorValid : true,
        items        : [
            {
                xtype      : 'textfield',
                fieldLabel : 'Test',
                allowBlank : false
            },
            {
                xtype      : 'ux-checkbox',
                fieldLabel : 'Test',
                allowBlank : false
            }
        ],
        buttons      : [
            {
                xtype    : 'button',
                text    : 'Submit',
                formBind : true
            }
        ]
    });

});

---

hmm, i think so, in fact i only wanted to know the syntax in the item area for saying that the checkbox must be
checked, so i guess i can also use allowBlank for checkbox just like for textfields ? I will try it tomorrow, thanks for your help

allowBlank won't work on it's own, so if you look at my example I actually extended Combobox to handle it.

ok ... thanks again