Re: Strange Undo action for caching based on transient properties

FROM : Mike Abdullah
DATE : Thu Nov 22 12:01:55 2007

You can "join" it with the previous undo like so:


NSManagedObjectContext *moc = [self managedObjectContext];
[moc processPendingChanges];
[[moc undoManager] disableUndoRegistration];

Do the work here

[moc processPendingChanges];
[[moc undoManager] enableUndoRegistration];

On 22 Nov 2007, at 03:40, Grigory Entin wrote:

> Hi,
>
> Probably this question is rather NSUndoManager related and not
> specific to the CoreData, but anyway.. I think it's quite natural to
> face this problem while working with CoreData/transient properties
> used for caching.. Any hints are appreciated. So..
>
> I'm using caching for some calculated properties and store the cached
> values in transient properties. All works fine (including Undo) and
> I'm pretty happy.
>
> However, there's a problem:
>

>>>

> When "caching" takes place it's recorded in undo manager - that's OK.
>
> Unfortunately, if such a caching happens *without* other changes in
> the data (e.g. when user just inspects calculated property, which
> value has not been cached), as the result, a "strange" (from the user
> perspective) Undo action becomes available.
>
> The Undo action results in "emptying" the cache - that's
> understandable from the developer perspective - it's not a question
> why it's available and what it does.

>>>

>
> So, I'd like to get rid of that effect (strange undo action available
> for user), however I need to keep the "caching" recorded for Undo and
> therefore "undoable" (and etc.).
>
> I'm thinking of "joining" that "caching"-related undo record with a
> previous "undo record" (or even "next" one), but I'm a bit lost on how
> to accomplish that, or whether there's a better solution.
>
> Any thoughts?
>
> Many thanks in advance,
> Grigory
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