I should be more clear: How would I set the scrollbar to position at the bottom of the datagrid (and then snap to the appropriate position when it the user is ready to load more data) as they do here? http://blog.tremend.ro/2009/03/02/flex-live-scroll-datagrid/
That would prevent users from retrieving too much data at one time & crashing the grid. --- In [email protected], "iloveyouwisconsin" <iloveyouwiscon...@...> wrote: > > It's not a traditional dataset. We're tweaking the structure slightly. > How would I do somthing like the following in Flex 4? > http://blog.tremend.ro/2009/03/02/flex-live-scroll-datagrid/ > > > > --- In [email protected], "Florian" <florian.salihovic@> wrote: > > > > But on the other Hand: why would you want to display more then a few > > hundred rows? > > > > There are way more efficient ways to walk through the data. > > > > --- In [email protected], "iloveyouwisconsin" <iloveyouwisconsin@> > > wrote: > > > > > > Thanks! I will look into that. For now, is there a quick and dirty way to > > > not show the scrollbar so users can't thumb through the results? I would > > > still need the ability to scroll through the datagrid, either through the > > > up/down arrow keys or the wheel on the mouse. > > > > > > thanks again! > > > > > > --- In [email protected], Jeffrey Vroom <jeff@> wrote: > > > > > > > > Back when I was at Adobe, I had a demo which did paging with 60K > > > > records in > > > > the query being scrolled. It probably could have done more if I tried > > > > since it was doing everything incrementally, though I'll admit the > > > > experience was not perfect, particularly if you moved the thumb too > > > > quickly. > > > > > > > > This was using the DataService with LCDS on the backend but it would be > > > > the > > > > same client code with "client data management" in flex builder. > > > > > > > > There were some tricks to deal with the big data sets: > > > > - paging automatically pages in objects but never releases the paged > > > > in > > > > objects by default. You can add this manually with the > > > > releaseItemsFromCollection method. You put this into a scroll event > > > > handler, periodically (but not too often) releasing any invisible data. > > > > - keeping the page request queue from getting too large. This was > > > > one > > > > problem I never solved completely... as you move the thumb, the data > > > > grid > > > > can request pages faster than they can be filled/released. There > > > > should be > > > > a way to either limit the page requests or keep them in a queue that > > > > can be > > > > flushed if you call the release method. > > > > > > > > I did a quick google search on "releaseItemsFromCollection" and it looks > > > > like the code from my demo made it into the LCDS docs. Not sure that > > > > even > > > > with this call it will do what you want but without that release call, > > > > the > > > > automatic paging stuff would eventually just keel-over from having too > > > > much > > > > in-memory. If that seems like the major problem, it might be worth > > > > trying > > > > it out. > > > > > > > > Jeff > > > > > > > > On Sun, Mar 14, 2010 at 11:28 AM, iloveyouwisconsin < > > > > iloveyouwisconsin@> wrote: > > > > > > > > > > > > > > > > > > > Maybe I'll have to wait until Flex 7 (or later) 'til they truly make > > > > > flex > > > > > able to handle large datasets smoothly. (I guess I'll also have to > > > > > advise > > > > > those at Adobe and the flex evangelists that what they define as a > > > > > "large" > > > > > dataset isn't large in practice. They probably need to moonlight as > > > > > interns > > > > > for a few of their customers to snapback into reality. There's no > > > > > company in > > > > > the real world that would define a large dataset as only a few > > > > > thousand > > > > > items) > > > > > > > > > > --- In [email protected] <flexcoders%40yahoogroups.com>, > > > > > "iloveyouwisconsin" <iloveyouwisconsin@> wrote: > > > > > > > > > > > > How many records is considered "too large" for a datagrid to > > > > > > handle? I am > > > > > using Flex 4 with Zend AMF & paging enabled. When I google it the > > > > > topic, > > > > > most seem to think that a "few thousand" is large, but that doesn't > > > > > seem > > > > > hardly anything to me. I thought Zend would do the trick but it isn't > > > > > anywhere near what I need. My 15 million records didn't go over too > > > > > well (I > > > > > can use the scroll wheel on my mouse to scroll through the records > > > > > but it > > > > > kept crashing when I tried to use the scrollbar on the datagrid to > > > > > jump > > > > > around). I ask because I don't want to have to jimmy around with code > > > > > until > > > > > I'm blue in the face trying to find something flex can handle. Can I > > > > > do 1 > > > > > million? 5,000? 500,000? I just want to be able to let users play > > > > > around w/ > > > > > the scrollbar on the datagrid without it crashing, is all (though I > > > > > realize > > > > > that the user's machine will play a big factor in performance. All of > > > > > my > > > > > users have computers that are no more than a couple yrs old) > > > > > > > > > > > > I also ask because I am sure others would like to know for their > > > > > projects....is there a more efficient way to get the data than Zend, > > > > > like > > > > > Livecycle or Coldfusion? I am willing to switch the backend up a bit > > > > > in > > > > > order to increase performance of my app. > > > > > > > > > > > > > > > > > > many thanks! > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
