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From: mcdonald@fornax.UUCP (Ken Mcdonald)
Newsgroups: comp.sys.next
Subject: Help, please, on making connections in IB
Message-ID: <2524@fornax.UUCP>
Date: 18 Apr 91 01:28:46 GMT
Distribution: na
Organization: School of Computing Science, SFU, Burnaby, B.C. Canada
Lines: 38

I'm having a few problems defining and sending action messages in
Interface Builder, and hope that some kind soul might be able to give
me some advice.

First, I'd like to use a subclass of the "TextField" class, which I call
"EntryField"; an EntryField object is defined to respond to one additional
action message (besides those defined by a standard text field), called
"update".  The idea is that the user enters data into this text field,
then presses a button to tell the application that the data in said
text field is what they want; the button sends an "update" message to the
EntryField object, which in turn sends an action message to the application
informing it of the presence of new data in the field.  This may be a bit
klugey, but that's OK--this is just a prototype.

The first problem is that I can't even create an object of class EntryField
in Interface Builder.  The class definition is no problem, but I can find
no way to specify that a normal TextField should actually be of type
EntryField, and when I try to Instantiate an EntryField object from the
Classes window, the Instantiate pulldown menu entry is disabled whenever
EntryField is the selected class.  So, having defined an EntryField class,
how do I create an object of this class in Interface Builder, so as to 
make connections to and from it?

My other question is very similar.  The application itself will be an
object of type "MyApp", which is a subclass of the Application class, with
some extra action messages and so forth.  Again, I can find no way to create
or refer to this object in Interface Builder; so there is no way, for
example, that I can tell my EntryField object that it should send a
"newData:" message to the application, in response to  the "update:" message
it just received.

This seems so simple that I'm sure I must be missing something.  Any advice
is most welcome, as without it, I can't even get started on this project.

Thanks in advance,
Ken McDonald
{mcdonald@cs.sfu.ca}
.