QueryCoveredRange - what is this event do?

[DAVE TESSITORE]

In your virtual grid, you use this event.. why? what is it used for? The help file does not go into detail. Can you explain what this event is doing on your Virtual grid demo? Thanks in advance.
Dave

[Administrator]

Notice in the sample, some cells actually cover several 'standard sized cells". For example, in the tutorial sample, cell 1,1 actually occupies (covers) cells (1,1), (1,2) and (1,3). QueryCoveredRange is the event where these covered ranges are provided on demand. In a non-virtual grid, you can set up covered ranges using grid.CoveredRanges.Add. But in a virtual where you might want a very large number of covered ranges, using this method is not practical. This is the reason for the QueryCoveredRange event.

If you do not need Covered Ranges, then you would not need this handler.