Can u give some more description or post the code?

Depending on what you need to do, you could create a lookup field; that
render a dropdownlist filled with the contents of a list.

I need to populate  a dropdown  list with the a field from a SP list. Then I would
like to connect it to another web  part based on what it selected from the
dropdown list.

In SPD I have created a dropdown  listbox and attached it to a SP list. But how
do I use that in a web  part?!?

You have to write code to achieve it, if you are developing a custom web
part.

Can you be more specific? It seems that the GUI tools have done the heavy
lifting, or at least I hope!

If custom web  part is going to be your approach, then you will have to
create either a user control and host it in a web part, or just create a web
part by creating controls inside it dynamically through code.

Well, I am trying to create a user control in SPD, and then add it to the
SmartPart, but apparently SPD doesn't add the codebehind file. And the SmartPart
can't pick up the user control without the codebehind. You'd think that if you
can create the control in SPD, that it wouldn't be that hard to somehow use it
in SP! It's like they show you the path to the Promised Land, then make you
wander in the desert for 40 years...

That's what you get for complaining...............

The problem is that SPD can't add the code behind because any page or
control that is stored in the content database is prohibited from containing
server side code. If you had a code behind with code in it the code
wouldn't compile anyway if the control is stored in the content database.
To write any kind of server side code requires the use of Visual Studio.

Actually I think it is more from lack of faith than complaining.

Well guess what? It appears that when I change the layout to dropdown  list, I
lose the ability to connect the web  parts! I'll keep at it today and see if I
can get it to work though.

Okay. What are you really trying to do? Your original post says you want to show
in one ˜webpart" what is selected in another ˜webpart". How should it be
displayed? Are you trying to populate  a grid or something? What is your output
requirement and why are you doing it? There are too many questions unanswered
right now to give you a solution. I am a big fan of jQuery but it depends on
what you are trying to get to in the end...

Simply put, I am trying to create a dropdown  list. When an item from that list
is selected, the corresponding records for that item need to display in a web
part. You could think of it like a customer dropdown list  that feeds an invoice
web part.

You can use a dataform web  part created in SPD and bound to the list  to do that.
Simply change the layout of the web part  to a dropdown  after you've bound it
to the data and then connect it to another dataform web part that has the data
you want to filter.

Really? I didn't know that. I'm off to do that right now!

Here's another question. How do I reference a SP list  from Visual Studio?

Are you looking for some code like this?

if (SiteCollectionURL == null)
{
SiteCollectionURL = SPContext.Current.Web.Url;
}

SPSite refSite = new SPSite(SiteCollectionURL);
SPWeb refWeb = refSite.OpenWeb("/");

SPList refList = refWeb.Lists[myListName];

And I will use any solution that gets a SP list  column into a dropdown  list
that I can then connect to another web  part! I've been back and forth with this
and still cannot figure a solution.

I have done this but it is fiddly. From memory, the steps using SharePoint
Designer are:

* Add a datasource control for the list  you want to use in the drop-down to the
page (you get this option in the datasources task pane)
* Add an ASP.NET dropdown  list control on the page
* Hook the dropdown list to the datasource control so it shows the desired
entries
* Create a DataForm web  Part (aka data view) showing the list you want to filter
* Define a parameter on the dataform web part  to point to the dropdown list
control
* Set up the filter to use the parameter

SharePoint puts code on the page, so it's dynamic i.e. as soon as you select
from the drop-down, the page will be refreshed with the filtered data. The
downside is that it is not Ajax, so the whole page re-displays, so the
experience is not fast or seamless.

I just tried this and get the error:Â "An unexpected error has occured"

And of course we can't debug it on SP2007!

You can debug using Visual Studio :) Not so helpful here, I know...

Have you checked the SharePoint logs in the 12 hive? Usually when you get
an obscure server-side error like that in SharePoint, you can get some more
details in the SP logs or in the Windows Event Log.

I googled and figured out how to modify the web.config so I get a more
meaningful error.

blog.thekid.me.uk/.../a-solution-to-quot-an-unexpected-err\
or-has-occurred-quot-in-wss-v3.aspx

I think I had something hosed with the data source or something on the page.
When I started with a clean page it worked fine!

Ah, good to know. Thanks for the tip, BTW; I didn't know about the
CallStack bit (just always turned off custom errors).