Preferred RunRev method to close a stack with Esc

[Dave Cragg]

On 11 Apr 2006, at 17:24, <mfstuart at cox.net> <mfstuart at cox.net> wrote:
>
> Scenario:
> The application is database oriented, with the user double-clicking
> on a table row to open a stack that displays all the fields,
> and data related to that selected row.
> The user is now on the sub-stack. If the user doesn't change
> anything, and presses Esc, the sub-stack should close
> with no warnings.
> If the user has changed data, and then presses Esc,
> I'd want to pop up an alert to the affect that they
> need to save or cancel changes.
> How is this done in RunRev?

This just one way.

First, you need a way to know if the user has changed data. The  
details of this will depend on your stack, but let's say you maintain  
a custom property that tracks whether changes have been made. So you  
might have a preOpenStack handler in the stack script to initially  
set the custom property to its "clean" state. Something like:

on preOpenStack
   set the cDirtyState of this stack to false
end preOpenStack

Then in the places you determine that a change has been made, you  
would set the custom property to true. For example, this might be in  
an exitField handler in a text field.

on exitField
   set the cDirtyState of this stack to true
end exitField

(But probably something more elaborate is needed, depending on your  
stack.)

Then in the stack script, you could have the following handler to  
catch the Escape Key.

on escapeKey
   if the cDirtyState of this stack then
      put "Do you want to save your changes?" into tString
      answer tString with "Save" or "Don't Save"
      if it is "Save" then
          ## do whatever you need to save the data here
      else
         close this stack
      end if
   else
       close this stack
   end if
end escapeKey


Cheers
Dave