On 9 Apr 2016, at 15:28, David via Scripting <scripting@lists.window-eyes.com>
wrote:
Got a project running here, where I could use a bit of educated feedback.
Imagine you have a selection of say 1000 CDs. You decide to catalogue all your
collection. You want to divide it into categories, and subcategories. Even,
under each subcategory, you may decide it would be nice to sorte each title
under its artist. And, somewhere in that herachi, you want to sort by country
of origin, and genre of the album. Poof, there we have one description that
might parallel with my project.
To best handle the categorizing issue, I thought to have things lined up in a
treeview. And I have the XML dialog and all the coding up going at the moment.
Things categorizes pretty nicely, and it is quite easy to navigate the tree,
decide on the title you want, and have the further operation performed from
there, once I decide on what to do with the selected title.
To give a bit of background, my "baby"-state of the project was done without
categories, and just lined up all titles in a listbox.
Now, that everything is working, another issue arises, and that is where I was
looking for some feedback.
When I had things just showing up in a simple listbox, populating this listbox
was done in a second or two - even with nearly 1000 entries. As I moved into
the tree-structure of my project, I am met with another reality. I can start
the dialog, and it will take anything between 2 and 4 minutes for the computer
to populate the tree. At the most, I'd say there is 5 levels on the tree. In
the root of the tree, you will find approximately 40-50 entries (main
categories).
I thought maybe something was wrong with my code. so I dropped out the lines of code that
inserts the very "leaves" - if you want to name them so - that is, the titles
of the albums. In reality, now we only have a treeview, with main categories,
subcategories, and artist names. No album titles. In this state, the tree populates in a
few seconds. Once I re-insert the lines that populate the last level, that is the album
titles, and that is where the big number of entries comes in, things are back to the real
slow processing time.
For inserting the Album title, I am using the same method as when creating the
different branch levels. That is, first to create a TV.NewItem, fill in its
Text and Data properties. Next, create an object pointing to the Parent Branch,
in my example the Artist name. And, finally, using the Children method to
Insert the entry of mine.
Dim ArtistName: ArtistName = "Jim Reeves"
Dim TVEntry: Set TVEntry = TV.NewItem
TVEntry.Text = "Best Of"
TVEntry.Data = 198901
Dim TVBranch: Set TVBranch = TV( ArtistName)
TVBranch.Children.Insert TVEntry, TVILast
This is a simplified snip-it of the code. I have not taken any security steps
in this snip-it.
What puzzles me, is why it takes so long to populate all the different branches, with all
the titles. As I stated, creating a tree with no "leaves", only all the
Category an subcategory-branches, took little or no time to populate. And even filling a
Listbox - although a far simpler constructed control - did not take an eternity either.
Questions for your consideration, would be:
- Is a Treeview supposed to be that slow to fill?
- Am I overlooking something here, maybe, that could cause this slow
processing? I.e, could I have used another method of inserting the last level?
- One alternative is, of course, to have all the categories and
subcategories show up in a treeview, and when the user have decided on the one
he wants to explore, he would tab over to a listbox that contains all the
entries in this subcategory. Haven't tried that last approach, and really would
have loved not to do it either, if possible. But I cannot afford to leave the
user with a several minutes long processing time, just for his collection to be
opened on the screen.
Worst thing is, that I loose speech while the tree is populated. So seemingly I
cannot even ask the user to do other computing while he is awaiting the long
processing. I just wondered if the very nature of the tree-structure conrol, is
such that it only is an effecient way of displaying a few entries?
Sorry for a rather lengthy explanation, but hope it all made a bit of sense. As
you may understand from the nature of the project, the individual entries on
the tree, are quite dynamic, so will have to insert them on the fly, and cannot
hard-code much other than the filling process, and then leave it to the user to
make the actual entries. Thanks for any feedback in this regard.
--
David
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