Listbox Memory Question

Posted on 2004-11-03
Last Modified: 2010-04-05
What are the biggest differences between a listbox and a virtual listbox?   The speed in which information is loaded?  The amount of memory taken up?  Where that memory is located?  I understand how each is created I was just wondering about speed and memory usage comparison.

I realize this is probably a no-brainer, I just thought I would come to the "source of great information" for a quick and highly reliable answer.  :-)

Question by:alexiat
    LVL 17

    Accepted Solution

    Virtual listbox are virtually unlimited in size because they just retrieve the information when you need them. A normal listview demands that you fill it completely with data before it can be shown.
    Imagine that you have 100.000 items, but only 30 of them would be visible. A virtual listview would just retrieve the 30 values that it needs to display. A normal listview needs to be filled with all those records first before you can use it. Filling it up costs a lot of time. And of course it would also eat up a lot of memory...

    Virtual listviews are especially useful with queries that return a huge amount of data. The data will be stored in the recordset somewhere and the virtual listview will just maneuver through this recordset. A normal listview needs to have a copy of all this data internally before it can start displaying, thus you'd double the amount of required memory. Besides, making that copy consumes a lot of time.

    Author Comment

    Thanks.  Exactly what I wanted to know.

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