How to design a high performance grid with VS 2005(specifically C#)

Question

I need to build a high performance winforms data grid using Visual Studio 2005, and I'm at a loss with where to start. I've build plenty of data grid applications, but none of those were very good when the data was constantly refreshing.

The grid is going to be roughly 100 rows by 40 columns, and each cell in the grid is going to update between 1 and 2 times a second(some cells possibly more). To me, this is the biggest drawback of the out of the box data grid, the repainting isn't very efficient.

Couple caveats

1) No third party vendors. This grid is backbone of all our applications, so while XCeed or Syncfusion or whatever might get us up and running faster, we'd slam into its limitations and be hosed. I'd rather put in the extra work up front, and have a grid that does exactly what we need.

2) I have access to Visual Studio 2008, so if it would be much better to start this in 2008, then I can do that. If its a tossup, I'd like to stick with 2005.

So whats the best approach here?

Answer 1

I am planning to build a grid control to do the same as pass time, but still haven't got time. Most of the commercial grid controls have big memory foot print and update is typically an issue.

My tips would be (if you go custom control) 1. Extend a Control (not UserControl or something similar). It will give you speed, without losing much. 2. In my case I was targeting the grid to contain more data. Say a million row with some 20-100 odd columns. In such scenarios it usually makes more sense to draw it yourself. Do not try to represent each cell by some Control (like say Label, TextBox, etc). They eat up a lot of resources (window handles, memory, etc). 3. Go MVC.

The idea is simple: At any given time, you can display limited amount of data, due to screen size limitations, Human eye limitation, etc So your viewport is very small even if you have gazillion rows and columns and the number of updates you have to do are no more than 5 per second to be any useful to read even if the data behind the grid id being updated gazillion times per second. Also remember even if the text/image to be displayed per cell is huge, the user is still limited by the cell size.

Caching styles (generic word to represent textsizes, fonts, Colors etc), also help in such scenario depending on how many of them you will be using in your grid.

There will be lot more work in getting some basic drawing (highlights, grid, boundaries, borders, etc) done to get various effects.

I don't recall exactly, but there was a c# .net grid on sourceforge, which can give you a good idea of how to start. That grid offered 2 options, VirtualGrid where the model data is not held by the grid making it very lightweight, and a Real grid (traditional) where the data storage is owned by the grid itself (mostly creating a duplicate, but depends on the application)

For a super-agile (in terms of updates), it might just be better to have a "VirtualGrid"

Just my thoughts

Answer 2

Try the grid from DevExpress or ComponentOne. I know from experience that the built-in grids are never going to be fast enough for anything but the most trivial of applications.

Answer 3

I would recommend the following approach if you have many cells that are updating at different rates. Rather than try to invalidate each cell each time the value changes you would be better off by limiting the refresh rate.

Have a timer that fires at a predefined rate, such as 4 times per second, and then each time it fires you repaint the cells that have changed since the last time around. You can then tweak the update rate in order to find the best compromise between performance and usability with some simple testing.

This has the advantage of not trying to update too often and so killing your CPU performance. It batches up changes between each refresh cycle and so two quick changes to a value that occur fractions of a second apart do not cause two refreshes when only the latest value is actually worth drawing.

Note this delayed drawing only applies to the rapid updates in value and does not apply to general drawing such as when the user moves the scroll bar. In that case you should draw as fast as the scroll events occur to give a nice smooth experience.

Answer 4

We use the Syncfusion grid control and from what I've seen it's pretty flexible if you take the time to modify it. I don't work with the control myself, one of my co-workers does all of the grid work but we've extended it to our needs pretty well including custom painting.

I know this isn't exactly answering your question, but it writing a control like this from scratch is going always going to be much more complicated than you anticipate, regardless of your anticipations. Since it'll be constantly updating I assume it's going to be databound which will be a chore in itself, especially to get it to be highly performant. Then there's debugging it.