Windows Server

Bil Simser [MVP] · Guest

I'm stuck. I think I'm caught between a rock and a hard place.

With SharePoint you have 3 ways to create web parts. Define the views
and all that stuff and drop it on a page. Create a DataView Web Part
(with FP2003) and drop it on the page. And create your own from scratch.

With the first two options, you can get all kinds of nice features like
column sorting, filtering, etc. Free. No coding required. With the
second option, you can have all kinds of great business logic happening
to render your information. Run off and talk to SAP, suck some data out
of your corporate Oracle system, do some financial calculations,
whatever. Then fire it off the web page all nice and neat for the user.
Problem is that I can't find any !%@#$%$# way to find a happy balance
between the two.

What if you want to aggregate across multiple types of items or items
that don't exist in a single library or list (like a domain collection)?
Let's say I have 500 sites under a portal and each one has a Task list
on it (we'll assume they're all from the same site definition). I write
a web part to recurse through all the sites, grabbing the task list and
finding all tasks assigned to Me and want to display them in my custom
web part, with filtering, paging, sorting, etc. that the ListViewWebPart
provides (assuming I have a list to point it at). I can't because I have
nothing to point the listview at. Unless I create a new list on the fly
(ugh) and populate it, but that's just plain ugly.

ListViewWebPart would be nice to inherit from then specify your own data
source (overriding the GetData method). However pretty much all of the
classes in Microsoft.SharePoint.* are sealed (except for WebPart) so
that's the only thing you can inherit from. For example, when you drag a
web part onto a page, SharePoint will use the ListViewWebPart from it's
arsenal to give you all those features people want (sorting, filtering,
etc.). However you can't inherit from ListViewWebPart, only WebPart. The
DataView Web Part is the same. I have to point it at a data source.
Grant you it's a little easier because you could point it at a web
service and have your web service do the heavy lifting, but still it's
not very elegant or easy for that matter and I've never seen anyone do
it.

Anyone have any insight into how to bridge what I think is a gap here?
While you can't inherit from a ListViewWebPart or a DataViewWebPart, you
can construct them in your custom web part. Problem is you're still
stuck having to point them at a physical source of information rather
than a collection of domain objects.

PS I'm putting together a blog around dissecting web parts and building
custom ones using a few helper classes so the pain of hand bombing
tables and cells and other HTML goodies is easier. Just want to try to
get an answer to this question before I complete the blog entry.

--
Bil Simser
http://weblogs.asp.net

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