Re: Hierarchical Trees Oracle Forms?

I have done this but it has been a while and I am at home so I don't have my notes with me.
For resources, you might try
www.experts-exchange.com
or technet.oracle.com
I do remember that the Developer book I was reading had an error in the example. My assumption in the quote below turned out to be true.
----- Quote

Your question was "I followed the instruction in "Oracle Developer Advanced Forms & Reports" page 625 in an attempt to build a hierarchical tree. The tree displayed properly but as soon as you tried to expand or colaps a branch it threw a C++ runtime error "assertion failed". I tryed an example from another source and got it to work, then I back tracked to see what the difference was.

As far as I can tell, the form needs to have at least 2 data blocks; one for the table which provides the data that drives the tree, and the other, a data block that contains only the tree widget. Not only do these two data block have to exits, the database table data block should come before the tree data block. Having the database data block come first causes it to be activated at runtime prior to navigating to the tree data block. Apparently as long as focus goes to the database data block some time prior to moving focus to the tree's data block, everything seems to work okay. i.e, you can expand and colaps the tree without throwing the C++ error, but if focus never goes to the database data block because there is none (as would be the case if using the example from the afore mentioned book) or the database data block is second in the list, so the form starts with focus on the tree's data block, then the C++ Assertion error will result. This is on NT, I don't know what would happen on Solaris.

So, now my question. Am I right? Do I need to have the database data block on the form? Does it need to acheive focus prior to focus on the tree's data block? And, if so, how can I design a form that simply shows the hierarchial tree and nothing else? As a work around, I put one data field from the database data block on my form and made the size of it 0,0. This seemed to work pretty good but does not strike me as a very elegant solution. Furthermore I fear that it may lead to other problems down the road. ----- end quote

hope this helps,
Mike

"Timothy Vaughan" <tim.vaughan_at_newcastle.edu.au> wrote in message news:3AC40FDB.7504_at_newcastle.edu.au...
> Question:
> I am just starting to use Oracle forms.
> I would like to know how abouts you get
> Hierarchical trees to work?
> What i am trying to do is have a tree which
> displays projects (from a database) and under
> each project a list of its tasks.
> And when you click on a projects Task, a seperate
> part of the form/canvas will display the task details
>
> eg.
>
> -project 1 | Details displayed of specific
> -tasks | task selected.
> -tasks |
> -tasks |
> +project 2 |
> -project 3 |
> -tasks |
> -tasks |
>
>
> Also does anyone know of an oracle forms help resources
> on the Net?
>
> Thanks for your help.
> Timothy
Received on Mon Apr 02 2001 - 04:29:25 CEST