You can use  beforeInitData for this purpose.

In navigator define for both edit and add beforeInitData event,

then use setColProp method for that field

setColProp('fieldname',editoptions:{readonly:true})  for edit and

setColProp('fieldname',editoptions:{readonly:false}) for add

Important Note. You will have trouble when you call this for first time

(it is bug), since the beforeInitData is called only when the form is

already created.

Regards

Tony

Considering that I am using navGrid:

1) Is it possible to show a field in modal form defined as readonly?

2) I need to define the same field as readonly=true to edit button and

readonly=false to add button. How I change it ?

Thanks.