Drop-down list issues

[Joemanc]

I'm fairly new to Infopath so bear with me.

I'm using Infopath with VB.NET. I have a drop-down list box bound to a
secondary data source(SQL) that is correctly pulling up client names. When I
pick a client name, I'd like to be able to populate a text box with the
associated client number for the record I picked. I'm using .NET code to
populate the drop-down. I'm trying to use rules to populate the client number
text box, but that is not working for me.

My rule is: Set a field's value: clientid = @client_id[@client_name = @Name]
where clientid is my text box
@client_id is the secondary data source field
@client_name = @Name(the drop down)

One thing I noticed, when I am creating the rule and trying to insert the
@Name part into the formula, I receive ._ instead of @Name. I have to type
@Name manually.

I did see that good example on infopathdev.com, which looks similiar to what
I am trying to do, but that is not working for me.
Am I missing something with the rule? Am I better off trying to get the
client numbers within the .NET code?

Joe