Set the field editor to edit mode, with a rendering rule of Case Status != Closed. Add a second field editor in read-only status and a rendering rule of Case Status = Closed.

We sometimes do this with individual fields in a single field editor. One occurrence of the field is rendered when a condition is true, and the other is rendered when the condition is false. As an example, if a certain field has a specific value or is not blank, another field appears to switch from optional to required.

You can also use “enable conditions” on the fields in the form.  This way you can use one form, expose the data in the “locked” form,  and prevent users from manipulating the data.  This is configured on a “field by field” basis (as opposed to rendering the whole form).  Pick the sort of work you want to do…

Thanks Mike and Rob.

If i will use 2 field editor and enable on the basis of the condition, then i need to make sure in future if i will add any field, it should be add in both Field editor. 

Is there any solution through snippet? I tried to change the mode of the field editor but it is not working.

We strongly recommend you stick with the declarative solution here.  While we stand behind our API,  when its functions are delivered via our declarative configuration tools - we are much more willing to make changes. 

In your case - it looks like the double work of maintaining two field editors going forward is a problem.  That means you should explore the conditional enablement feature on each of the fields in the field editor.   That can be your solution here.