EXCEL like grid

I'm trying to create an Avalon custom control simulating the Excel
grid. It should have to be able to handle 5000 rows by 300 columns of
data.

My first approach was overriding the OnRender method and drawing the
visible fields, but the performance decreases when adding scroll
support because I need to repaint my grid all the time.

Another way is having a Grid element with the visible rows and columns,
and removing and adding the corresponding rows and columns to simulate
scroll.

What do you think? What would be a good approach?

Thanks in advance.

First step- read through some WPF tutorials. Not to be blunt, but
overriding OnRender is the last thing you want to do here and you're
missing a few key points about WPF (like retained visuals).

Take a look at ListView, that'd be a good starting place. I don't know
if it has virtualization like ListBox does, but if not then thats what
you need to add.

Is it possible to implement a Grid that supports virtualization? Is
that the right way to solve my problem?

In that case, should I choose Grid and/or VirtualPanel as base classes?
Should I implement IScrollInfo in that class?

Where can I find some information or samples to help me understand how
to implement a solution to my problem taking advantage of what Avalon
offers.

Thanks.

lcantelmo@gmail.com wrote:

> Is it possible to implement a Grid that supports virtualization? Is
> that the right way to solve my problem?

It is, but it's no easy task... so be prepared to do a lot of work.

> In that case, should I choose Grid and/or VirtualPanel as base
> classes?

This is a question I haven't spent enough time investigating. Looking at
the way VirtualStackPanel is implemented it seems like you should inherit
from VirtualPanel, but what that means is that you're stuck implementing
ALL the layout functionality of Grid again. I'm not sure if there's a way
to inherit from Grid, implement just IScrollInfo yourself and "feed" the
correct items to the base Grid.

> Should I implement IScrollInfo in that class?

Yes, that's how you know when to create/destroy controls that lie outside
of the current viewport.

> Where can I find some information or samples to help me understand how
> to implement a solution to my problem taking advantage of what Avalon
> offers.

AFAIK there are none. Virtualization is not an easy task and there's no holy
grail implementation that fits all possible layout needs. That's my guess
as to why why there's only VirtualizingStackPanel in the WPF library right
now.

HTH,
Drew