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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