Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Do FORM vs. createobject()
Message
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
00859255
Message ID:
00859396
Vues:
22
>>>>>... grids, to ListViews.
>>>>
>>>
>>>>Benefits (and pros and cons?
>>>
>>>Pros:
>>>LV has a real time slider (opposed to grid's snap to)
>>>LV is cached, pointers are set quickly
>>>LV allows [all] column sorts without index
>>>LV offers multi-select
>>>LV offers image
>>>LV is what consumers are "used" to (grid is mostly a VFP phenomena)
>>>LV is fast
>>>LV PRG frameworks are easily generalized and adapt well to other projects
>>>LV automation script is the same as most of the other "sexy" OCX controls
>>>LV scripting skills enhance our practical understanding of OOP.
>>>
>>>Cons:
>>>Cannot bind to a data source. Rows and columns must be programtically added and updated (no direct entry except for "main" or listitem column - script code can be tedious:-) Grids may be edited directly (like a spread sheet). It could be argued, however, that [over] reliance on grid entry solutions may not be putting the best face on Foxpro.
>>>
>>>Skills with VFP's mean record pointing machine. SEEK and loop, the the speed of light, through the data rather than SELECT. To retrieve data, code must back point to the source "cursor". Edit changes will have to be written back to both source cursor and LV control (tedious script).
>>>
>>>Over zealous truncation of column values related to column width. Puts those little "......" dots, when the column is plenty wide.
>>>
>>>Imagecontrol learning curve should bmps or icons be used with LV
>>>
>>>VB Script learning curve
>>>
>>>They become addictive:-)
>>
>>Terry,
>>I am taxing my memory and possibly confusing two controls * but * don't LV slow down with over 100 records?
>
>The question of how much data "really" needs to be presented to a user is still an open issue. Developers are used to it. It is our trade. Most controls [would seem to] prefer small data sets (as do users). Putting a 1000 or so in a combo (or ListBOX) may be a bit over the top. But for navigation controls, let common sense be your guide.
>
>Regarding LV speed - I have one LV with 1,100 and it is a smooth as one with eleven. If you have a drive with a bunch of folders and files, you might be able to assess LV's performance by evaluating with windows explorer. View in "detail mode". The combination of treeview/listview as presented by windows explorer is a good study on how to present so-called heirarchal relations.

Terry,
Typically, the control source for the grid (or listbox) would be a cursor.
So, I would have to loop through the cursor and add the rows to the listbox, correct? That could introduce a delay in the object appearing with data, correct?
The idea of sorting without indexing is definately attractive.
Regards,

Allan Coganovitch
allanc@proven-solutions.com
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform