Virtual Grid Question

[Trevor Redfern]

Is there an event, or way for the virtual grid to request a block of data as opposed to a single cell at a time. I noticed that all the samples show a tiny grid with only 10 rows and 6 columns showing, and everything scrolls fine.

Expand that same grid up to a 30+ rows with 10+ visible columns, and we have a whole new story. Performs on a page scroll drops to a crawl. I'm assuming this is due to requesting each cell on a one by one basis. It'd be nice to get a single request for a rectangle of data, and be able to send it at once.

Trevor

[Clay Burch]

I think the most likely explanation for the paging slowdown is not the cell by cell retrieving of the data, but the cell by cell GDI+ drawing of the 30+ x 10+ different cells. Each cell can potentially have a different font, backcolor, string value, etc. If you just try to use Graphics.DrawString and display 300+ different strings in real-time as you move a scrollbar, you will notice a slowdown as the drawing cannot keep up with the scrollbar moves.

With GDI, there was no slowdown in this situation.

We are trying to improve the performance in this area, but major improvements may have to wait until Microsoft speeds up GDI+.

In the meantime, if you need to display 30+x10+ cells, you might want to consider turning off the thumb scrolling support, and enabling the scrolltip support. With these settings, the scrolltip gives you the dynamic feedback of the scrolling behavior. Since it only paints a small window (and not 30+ x 10+ cells), you'll see very responsive scrolling. The properties are GridControl.VerticalThumbTrack and GridControl.VerticalScrollTips

[Clay Burch]

We are working on improvements to Essential Grid for the 1.1 release that will improve this scrolling performance. These improvements, along hierarchical grid support, are top priorities for this release. This 1.1 release is tentatively scheduled for 6-8 weeks after the 1.0 release. The 1.0 release will be available in the next few days.