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databinding with multiple observables [message #733986]

Thu, 06 October 2011 08:25

Jesper Eskilson

Messages: 134
Registered: July 2009

Senior Member

Hello,

I have a general question of approach. I have a dialog where some
buttons enabled-state depends on several fields in the model object. How
is the typical way of handling this? From the documentation I've read,
databinding is always about connecting *two* observables.

In this concrete case I'm using SWT with databindings to a EMF model
object, and one of the buttons should be enabled if at least one of two
checkboxes as checked/selected.

One solution I can think of (for this case) is to introduce a separate
model field containing the enabled-state of the button and then use
regular EMF notifications to update that field when either one of the
checkboxes changes state.

--
/Jesper

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Re: databinding with multiple observables [message #733988 is a reply to message #733986]

Thu, 06 October 2011 08:34

Thomas Schindl

Messages: 6651
Registered: July 2009

Senior Member

Hi,

You could create a ComputedValue which itself connects to the domain
model attributes. The computed value is then bound to the
Buttons-Enabled-Property.

Tom

Am 06.10.11 10:25, schrieb Jesper Eskilson:
> Hello,
>
> I have a general question of approach. I have a dialog where some
> buttons enabled-state depends on several fields in the model object. How
> is the typical way of handling this? From the documentation I've read,
> databinding is always about connecting *two* observables.
>
> In this concrete case I'm using SWT with databindings to a EMF model
> object, and one of the buttons should be enabled if at least one of two
> checkboxes as checked/selected.
>
> One solution I can think of (for this case) is to introduce a separate
> model field containing the enabled-state of the button and then use
> regular EMF notifications to update that field when either one of the
> checkboxes changes state.
>
> --
> /Jesper

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Re: databinding with multiple observables [message #736243 is a reply to message #733988]

Thu, 13 October 2011 20:26

Jesper Eskilson

Messages: 134
Registered: July 2009

Senior Member

Tom Schindl skrev 2011-10-06 10:34:
> Hi,
>
> You could create a ComputedValue which itself connects to the domain
> model attributes. The computed value is then bound to the
> Buttons-Enabled-Property.

Ok, thanks.

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