RE: Window Freeze

Question

Yes, in answer to your final question, it is a bad idea to have one
window/thread directly invoke a method on a different window if the method
touches widgets. Especially in more recent versions of Forte where they
have made more extensive use of the Windows95 facilities which equate
windows and threads in a very strong way, in my understanding. This is in
fact one very easy way to produce a client seg fault, if I remember right,
if the called method changes the contents of a "mapped attribute" for a
widget on the other window..
So yes, you should be posting a message on the parent window and allowing
the normal multitasking to switch to that thread and get around to handling
the event and refreshing the node.
-Greg
-----Original Message-----
From: Jason de Cean [SMTP:[email protected]]
Sent: Thursday, March 25, 1999 12:34 AM
To: 'Forte Users'
Subject: Window Freeze
Hi,
We have a list form (listview) that has a child details form. The user
selects an item from the list and this instantiates the child window
which is populated with a clone of the selected data object. The user is
then able to change the details and save these changes, and the update
object with the new values is passed back to the parent list so that
item details can be displayed.
Now, in order to pass the object back to the parent list the child
window has a reference to the parent and invokes a method directly on
the parent window object, eg. m_SaveItem(doObject). This method then
replaces the existing object with this new object and refreshes the list
view.
The problems is sometimes the child window freezes when the save occurs.
The exact events that occur are:
1. User Clicks Save
2. Disable Save Button
3. Save In Database (invoke so method)
4. <freeze>
If the user then moves the mouse cursor off the child window and gives
focus back to the parent list, the freeze ends as everything continues
normally:
5. Move mouse cursor to parent list.
6. List is refreshed.
7. Save button is reenabled.
The child window is modaless and is therefore a separate thread to the
parent. The freeze only ends when focus is given to the parent list.
Moving focus to other child windows or other windows applications has no
effect.
So, is it possible that the problem is being caused by a deadlock
between the 2 threads? The ListView actually belongs to Thread1, but is
being updated by Thread2 during the callback to the parent's
m_SaveItem() method. Is it dangerous in Forte to refresh a widget using
a different thread to the one handling the event loop (in which case we
could post an event to the form instead)?
Any other ideas?
Jace.
Jason de Cean
Genisys Team
Lumley Technology Limited
Level 8, 55 Sussex St
Sydney, Australia (+61)
Ph. 02 9248 1321
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Answer 1

allready using it. I think I'm gonna try a faster usb dongle, and see if it was a signal strength thing. There might have been too much a/v information the comp was trying to process.
The present usb dongle is connected @ 65Mbits, so it should be plenty of speed, so process of elimination points to the receiver. Fingers crossed
Thanks for your reply